I recently compared the Mozilla project's state 5 years ago with today, and cried Victory. I reckon I declared victory in a provocative way, as I must say. Of course, a lot has been achieved during the past 10 years, but Mozilla is now facing another set of challenges. Here is an attempt to list them:

More competition on the desktop

Microsoft finally seems to get its acts together and is reinvesting in Internet Explorer. IE7 was just a start, but IE8 sounds promising, at least in terms of Web standards support, which is good. It's a bit too early to discuss user experience improvements, but Microsoft may do better this time...

Likewise, Apple is not resting on its laurels. Webkit is quite impressive in terms of performance. Safari has an edge over Firefox as it is shipping with all new Macs, just like IE is shipping with all PCs because it's bundled with Windows.

Mobile

Mobile is the new frontier when it comes to Web browsing. The current version of Gecko has made a very significant progress in terms of memory usage and performance, rendering it a good opponent on the Mobile browsing market. However, Opera is entrenched there and Webkit has made good strides in this area. The mobile industry is changing as it increasingly adopts Open-Source, while users demand "real" Internet access instead of the old "walled garden" approach. Pieces of the puzzle are falling into place, but it's not going to be an easy win for Mozilla.

Online services

Online services that are tied to the browser are becoming important in order to improve user experience, as several extensions such as the late Google BrowserSync, Foxmarks and some others have demonstrated. Synchronizing bookmarks across several Firefox instances was interesting to many people, but now that Firefox 3 and its AwesomeBar are spreading like fire (no pun intended), bookmarks and navigation history are proving to be increasingly valuable to users. Mozilla Weave, in this regard, is very promising.

Apple now has MobileMe and Me.com, and if I was in Microsoft's shoes, I'd do something along these lines for Windows around Live.com, so we can expect some heat to happen around online services dedicated to client applications.

The Open Web versus proprietary stacks

This is the issue that worries me the most... While Microsoft has promised that IE8 will support Web standards, it looks like it wants to impose Silverlight as the technology for "serious" development of applications that need to run inside a browser, in way very similar to Adobe's with Flash. If Mozilla's mission is to defend the Open Web, what happens if the Open Web is made obsolete by proprietary technologies?

Conclusion

When you think about it, what Mozilla has achieved so far, though very impressive, seems almost easy when compared to the challenges that we're now facing...

I listed these challenges in order to prove one point: Mozilla indeed is very successful, but it should not get distracted by exciting, yet out-of-reach, goals. This could cause Mozilla to lose its (main) focus and then fail to overcome its upcoming challenges.

However, Mozilla does need bold goals and an ambitious direction to keep its community together. In this regard, having Mark Surman joining Mozilla Foundation as Executive Director is very good news.