After a very long interval, the dev channel of google chrome has been updated to version 4.0.288.1. To see if your chrome install has been updated, check Chrome -> About Google Chrome menu. Chrome should automatically check for updates and tell you whether there are any available. If you were on dev channel before you would have been automatically migrated to Beta channel and so you might have to get back into the dev channel by manually installing this version.
Extensions have been enabled and they have gained new capabilities on mac. Flash performance is still terrible, so you are advised to use one of the many flash blocking extensions available including mine (Kill Flash). Bookmark sync is enabled (which introduces a bug) but bookmark manager is still not available although chrome has been making some progress in this.
Anyone who is using mac on chrome will greatly benefit from extension support. So this is a must-update version for all mac users. Bringing back the extensions makes the browser more pleasant. to use. :)