It may seem as if the Firefox 3 release cycle went on forever, especially if you hopped on board with the earliest betas. Many of us are still catching our breath after the version 3 release, waiting for add-ons to be updated and tweaking our preferences. But don't rest too long: Firefox 3.1 is right around the corner.
According to the minutes of the most recent planning meeting, the first alpha of Firefox 3.1 is due in July - probably early next week - and the final version is targeted for the end of this year or the start of 2009. Judging by the various information available on the various developer sites, it seems fair to characterize this release as evolutionary rather than revolutionary - the developers are picking up some long-postponed work items and doing some fine tuning, but it won't have the sort of complete UI and rendering overhaul that characterized version 3.
Among the things that are scheduled to be in Firefox 3.1 are a few lingering fixes for compatibility with the "Acid 3" CSS test, tag management improvements for bookmarks, and a private browsing model that makes sure no potentially-identifiable information is saved from your session. Other improvements may include better video support, SVG changes, and some more eye candy for working with multiple tabs.
If you're really interested, you don't even have to wait for the alpha build to find out what's happening. Just download and install the latest nightly build and install it for yourself. Just remember to put it in a separate folder so you can go back to 3.0 when you're done poking around. As I write this, the pre-alpha build doesn't like many of my add-ons, but the Ctrl+Tab tab switcher, complete with thumbnails, is very nice.