They've simply moved to a time-based release schedule rather than basing it on features.
So every 3 months a new major version will be released, whereas before they would attempt to add a bunch of new features and wait until it was working before releasing.
Actually, I think they will be releasing a major version every 6 WEEKs. The current Firefox 6 is on Aurora channel for 2 more weeks and then on beta for 6 weeks. Then the release is set. The 2 week delay only exists between FF 5 (which was done faster) and FF 6 and will not exist in next versions.
Do-not-track: a pointless header that anybody who WOULD be inclined to track you would ignore. I don't see any value in this header, it does NOTHING to improve privacy. What would be a nice addition to the android version would be, rather than this pointlessness, PRIVATE BROWSING (no storage of cache/history/cookies/anything to device).
That DNT header is not a cure-all as the standards don't require sites to honor it, so indeed this is a pointless feature at the moment
FF5 is noticeably faster for sure...some memory leaks fixed too
Obviously Mozilla does, otherwise they wouldn't have switched to the "My version number dick is bigger than yours" system.
It pretty much guarantees more exposure on tech sites, I dare say 'version 5 is out!' yields more coverage than 'version 4.1 is out!' no matter what the actual improvements are.
Also faster turnaround on major version numbers likely gives the impression that more is happening with the software than actually is, worked for Chrome ('hory shet, it's already at version 13!! this software must be so great!!').