Firefox Sync, Mozilla’s online syncing service available for Firefox users on desktop and mobile platforms, will be soon limited to 25 MB of data per user. Though this limit will not affect majority of the users, says Mozilla.
According to the stats provided by Mozilla, “The average user uses about 1 MB of data, with an average of 83 bookmarks, 11 passwords, and 1500 history items. Even around the 90th percentile of users, the disk usage is under 6 MB, with around 700 bookmarks, 12000 history items, and 100 passwords.”. This clearly indicates that a typical Firefox user will not be affected with this policy change.

Beyond Limit?
Once a user reaches a certain limit, Firefox Sync will warn him/her. After completing the 25 MB quota, user will be unable to save any further information on Mozilla’s servers. Mozilla is considering various options to provide extra storage space to the users.
Moreover, the technology behind Firefox Sync is completely open sourced and can be implemented on other servers by the users or independent service providers to sync data without any space limit.
Chrome and Opera already provide similar sync service to synchronize bookmarks, saved passwords and history items.