Saw this in ReadWriteWeb. The developer’s version of Google Chrome has implemented sync-ing for extensions. This implies that you can install Chrome extensions on your home PC and automatically have your Chrome browser on your work PC, netbook, new PCs, etc, automatically download and install your extensions. Without Chrome Extension, you would have to manually keep track and install the extensions on each PC. However, apparently this feature isn’t yet very stable and most probably isn’t going to make it to “release” anytime soon.
Currently, Chrome (stable release version) only supports Bookmark Sync, where your bookmarks can be automatically synced across different PCs.
Similar offerings include Firefox Sync. But while Firefox Sync is able to sync browsing history, stored passwords, and even open tabs, in addition to bookmarks, it is still not able to sync Firefox extensions.