This is the transcript of the chat with Mike Beltzner as part of Support Firefox Day, formatted for better reading.

All sessions happened on IRC with questions from the public moderated by David Tenser, Mozilla Support lead.

What frustrates you most about the Firefox 3 UI?

Heh, great question. There are a couple of things that are frustrating to me, both at the UI and underlying infrastructure level.

At the UI level, I’m frustrated that we’re not animating more, and not trying to offer more “emergent” interfaces that help users complete tasks based on what we can infer from the task the user is trying to complete.

So, specifically, I want the location bar to be even smarter, and things like saving pages and downloading files to be even smarter. And I want them to animate fluidly so that users can understand how one part of the UI associates with the next, or how one operation flows into the next.

At the underlying level, I’m excited about new platform enhancements like Compositor as it will let us float chrome over parts of the page more naturally, and of course better threading models will help us give users progress indication.

Hello, what do you consider as the most influential UI Firefox 3 advantages over competing browsers and why?

Another good question!  The biggest advantage that a Firefox 3 user has over anyone else is that their browser learns based on how they use it.

The Smart Location Bar and Download Manager, for instance, help users search through the places they’ve been and the things they’ve downloaded, which makes the browser smarter and more personal. So instead of having to remember the name of that place where you saw a funny video about monkeys, you can just type in “funny monkey” and get where you’re going. Or instead of having to remember where you downloaded that interesting research paper, you can search through your downloads and go back to that site.

It really changes the way that you browse, and I think people are going to really love it.

It’s all about searching, basically?

It’s certainly about recognizing that people tend to revisit sites a lot, and until now, it was hard to do that. Adding search over local resources was a natural way to solve that problem. But really, that, coupled with the performance improvements (yes, that’s part of usability and design!) and security improvements (yes, important for usability and design!) make Firefox 3 an incredible product.

(David Tenser: Incidentally, the Firefox Support website is also based on the idea of searching for your problems (support.mozilla.com)… yes, a plug for support :p)

In Firefox 3, which UI feature is the one you’re the most proud of?

Hmm. (beltzner ponders)

I’m personally proud of being able to select all entries in the download manager, but that’s only because it was one of my first real patches ;)
But that’s not really a hugely important feature. I think I’m most proud of the Smart Location Bar (also known as the Awesomebar). I think it will be as important a shift in web browsers as tabbed browsing was.

Besides the obvious UI changes, what else about the download manager changed in Firefox 3?

Well, the biggest thing was the addition of support for pausing and resuming downloads. This is done either explicitly through pressing the pause and resume buttons, or automatically when you close Firefox in the middle of a download or turn off your computer.  The next time Firefox starts, we resume the download.

Do you think the location bar and search bar will be merged, and if so, when?

You can also now search your downloads by file or download host name. And if you’re on Windows, we scan downloads with your virus scanner before letting you open them.
Do I think they’ll merge? Perhaps eventually, yes. Mozilla has actually tried that before, back in Mozilla Suite days. It didn’t work that well, and users found it hard to differentiate. That’s why they went with the broken out search bar in Firefox 1.0. I think you’ll be seeing some experiments from Labs in the near future about merging the two UI spaces again, and making it more task based.

(David Tenser: What does task based mean?)

We want to enable things like mapping, sharing, emailing, as well as searching and navigating.  Right now each bar has it’s own task: The Location bar is for navigating. The search bar is for searching. We’re starting to see overlap in Firefox 3: the Location Bar is for searching locally, the Search bar for searching the web.
Eventually we want to add other tasks: mapping, sharing, creating, etc. Of course, we have to balance all of this against efficiency.

You say you *think* people are going to love it, what testing has been done (aside from power users and Slashdot) on the browser’s UI?”

The 1.6 million people using our beta and release candidate builds are more than just power users, and we’ve gathered feedback from a bunch of audiences. Some of this I’m very comfortable just asserting from watching people of various levels of expertese interact with the bar, too.

Classic lab based user testing is costly in terms of time and investment, and a good way to determine if your feature is discoverable, but not a great way to design. Design takes insight, observation and inference. We had the insight that a user’s history was a great predictor of where they wanted to go through observation, and inferred that search was a good metaphor to expose it.

Does user support issues sometimes help you figure out the right approach in design decisions?
Yes, of course. Here’s an example: “I lost my bookmarks, help!” was one of the most common support questions. That led to us totally rebuilding the infrastructure on which bookmarks were based, and adding in an automatic backup function, as well as a restore tool.

What do you think about IE8 implementing the domain highlighting that was tried a lot for FF3 but finally backed out?

I think they can expect to see some of the same resistance that we saw from within our community. And IE has run into this problem before. The move to IE7′s UI disoriented a *lot* of IE users. This is a careful balance a designer has to maintain: how can we introduce new thigns without disorienting our users.

I believe the domain highlighting is something we’ll revisit in the future, but we need to make sure that we do it in a way that is: not a negative impact on performance, and not disorienting to users.

One of the really exciting areas of Firefox 3 is easier integration with sites. Add-ons and Support are two obvious examples. Can you talk some about that?

Sure thing! In addition to integrating with addons.mozilla.org and support.mozilla.org, we’ve added support for webmail and web calendaring applications to register themselves as handlers for those protocols.
So, for example, Yahoo! Mail or 30 Boxes can open the mailto: and webcal: links you run into. We want to do more there, but need to work with web developer communities to build the right standards and specs.

(David Tenser: actually support.mozilla.com :) )

(use a redirect!) So, that’s one thing that frustrates me. The .org/.com split in our websites is confusing to everyone. We should just redirect them all so that everything works. Or show pages like http://ytmnd.org :)

(David Tenser: I agree. )

What application UIs inspire you?

(Hint to applicants: that’s a question I ask all people who interview!)

(David Tenser: Note that everyone!)

(beltzner ponders for a second)
I really like a lot of aspects of a bunch of UIs. One thing that really impressed me was when Flickr added support for video. They just fit it in right into their existing UI without doing much else. It was simple, and it worked well.

The iPhone UI is cool, but more for the gestural support than anything else, and perhaps the physics model.
Making things bounce and animate is very important in UI. It makes the elements feel more “human” and real, which makes them more pleasant to interact with.

(David Tenser: Here comes a long question.)

I am sure I’m not the only one who noticed a change in the approach for the UI design for FF3. Decisions like using different colors for the location bar menu, based on cognitive studies. I don’t remember reading or hearing about that previously on Firefox development. What has changed? More reading? Classes? People?

What has changed is Alex Faaborg and Madhava Enros. :) My team has grown. Madhava and Alex have been bringing their considerable skills to bear on design questions, which has increased our ability to respond and discuss these issues that come up.

For Firefox 2, it was me and Mike Connor and the Firefox development team. For Firefox 3, it was me, Mike Connor, Alex Faaborg and the Firefox development team. We’ve also started to shift the way we talk about design.

That’s not just been through adding people to my team, but a shift in the entire organization. Everyone now looks at UI with the frame of how users will experience it, and how those experiences can be improved. And with more of us on the team blogging about it, everyone’s learning better ways to improve the experiences.

So there’ve been a lot of changes, really, and all for the better.

What is your favorite Opera feature?

Uhm. Hm. The uninstall? I’m a little stumped, to be honest.

I’m not that mean. They have some good ideas, but I often find that they expose them in ways which aren’t very subtle. Speed dial is a little neat, but it’s also visually very noisy. I would rather they have taken up less space on the page.

Do you use many web applications, and how do you think web applications in Firefox will progress in future?

I use Zimbra, Gmail, GReader, Flickr, YouTube, Facebook, Friendfeed, MoveableType, Zoho Office, Springnote, and others. Oh, Mibbit, when I’m travelling.

So yeah, I use a lot. I can’t actually think of a single thing I can’t do in a web app.

What I love about Firefox and Mozilla is that we’re interested in increasing the capabilities of the web.
I’m really excited to see what things get done with our new offline support, as well as the new SVG and Canvas features. In the future, 3D canvas and <video> and <audio> tags will basically round out the stack.

In terms of Firefox, I think we will eventually integrate Prism or Prism like functionality. And make it even easier for web apps to interact as real desktop applications.

(David Tenser: So it seems Firefox is expanding into other projects like Prism, Mobile, etc)

You can see us moving along those lines with our web application support.

Will you be leading the Firefox Mobile UI efforts as well?

Right now Madhava Enros is leading the UI efforts on the Fennec project, but he’s not the only one contributing ideas. Aza Raskin, Jennifer Boriss (our newest team member!) and I are all working on design ideas together, along with people like Jonathan Nightingale, Gavin Sharp, Stuart Parmenter and others. And of course, all in the public.

My role will be oversight and advisory, but I’m already pretty excited by the ideas I’m seeing on mobile.

What do you think about fulltext page search in adress bar?

Fulltext page search in the address bar ends up being very, very noisy. If we can get it to work right, we will, but early experiments showed that it picked up a lot of irrelevant content from the page and made it harder, not easier, to find pages.
We might want to include full page search in a deeper, more advanced search UI sometime in the future. But as the default search, it didn’t work well.

Do you have ideas for web startups, such as new sites or new business models made possible by the new features in modern web browsers?

Well, if you think about it, web browsers now offer you a way to deploy an application, have it work online or offline, have it show rich and interactive UIs, and have it benefit from the network effect and the “works-anywhere” model of computing.

This has been a long time dream of application vendors, and the rationale behind things like Java and other application models: the promise of “write-once, run anywhere”. As we move on to mobile devices, this same rich technology stack will come along with us. So you’ll be able to write an online app, or a Firefox Add-On, and have it work as an app on a mobile device. Connected or not.

Sounds like there’s a lot of potential in that, for me. One thing that’s always amazed me is the web application and add-on developer communities ability to be more creative than anyone can imagine!

(David Tenser: Thank you very much Mike for taking the time to do this. Hopefully everyone in the channel learned something new.)