Firefox 4 beta 1 is here – what’s in it for web developers? ✩ Mozilla Hacks – the Web developer blog

Today we’re releasing the first beta-quality version of Firefox 4, which starts us down the path to a final release of Firefox 4. We’re handling this beta differently than we’ve done other releases. In previous betas we’ve made milestone-like releases. For this beta we’ll be making more frequent updates during the beta program. So if you download the beta build and run it you’ll likely get updates every two to three weeks, instead of a couple of months apart. We believe that this will give us the ability to reply to people’s feedback quickly and get fixes and changes tested earlier. This, in turn, will mean we’ll be able to release a much higher quality browser as a result.