Interview: Firefox 3's interface design guru talks

What lessons did you learn when you were developing Firefox 3?

Mike Beltzner "The most useful features and the most popular features have always been those that help connect people with their tasks online, their sites online and the content they want to see. So that can be features that the user never sees, such as our JavaScript engine and rendering performance that make Firefox a faster browser. They can even be user-facing features such as tabbed browsing, which was a very popular feature in earlier versions of Firefox and allows people to get more stuff done at the same time online.

"We have continued this task focus throughout the iterations of the browser, so obviously Firefox 1 popularised tabbed browsing and we went further with Firefox 2 and the spell checker – we realised people were writing a lot of content more than they were reading, so we have spell check built in. We also added things like session restore so you can close your browser and pick up where you were with windows and tabs later on.

"We added search suggestion, so if you started typing something the browser would start giving you suggestions. If you didn't quite know how to spell Britney Spears' last name, the search suggestions would help you out. Firefox 3 continues that. The biggest feature we added is a search against your local history and location bar.

"Sometimes it can be hard to find that really funny video you saw a little while ago or that really cool page you liked. Now the location bar means that you can search against your local browser history and bookmarks based on the title of the page. So if you saw a page with a cool pair of jeans a while ago, you can just type 'jeans' into the location bar and we'll show you the list of pages that had something to do with jeans. The way we are doing this technically is we can store this information in a database like the search engines are doing except it's more relevant to the end user because it's their subset of the web."

Would users be confused by that, since they usually type in a URL?

"We have designed it to be an emergent sort of thing, so if you're used to the location bar being matched with a URL you typed before, it will still do that. If I'm used to typing a web address, I will still see matches against that web address. But I will also see that it matches against the title.

"We have designed all of our new features like this. Another new feature is one-click bookmarking, so instead of a lot of forethought about bookmarking, you can just click the star. But if you are used to bookmarking using the menu system, it still does the same thing. They're ways of making it easier to learn new features."

There's a sign in your lobby that says you support open standards. What is the trade-off between supporting standards and being fast and reliable? How do you fight that battle?

"We have found with Firefox 3 that it hasn't been a hard battle to fight at all; we haven't had to make a lot of sacrifices. It's not that often that a piece of software comes out with more features 'at the glass' for users as well as more features under the hood for web developers in terms of a faster rendering engine. It's faster, uses less memory and takes a smaller footprint on your system.

"We're working closely with the standards bodies to help develop those standards in ways that make sense. Overtime it's just a matter of rationalising that engineering effort and making sure what is going on under the hood is as fast as possible."