I find it a useful feature for the forum software to save a draft for later editing and posting. I am wondering what limitations there may be on this. For example a time limit, only one draft or one per sub-forum, or if they get lost if your cookies get erased.
On this site, drafts appear to be saved automatically. Cookies aren't a problem, as the drafts are saved server-side -- I've started writing things on the PC, then they come up on my iPad.
Drafts are saved every 60 sec, and stored for 24 hrs. You can have multiple drafts. The drafts are stored in the database, they don't use cookies so they persist across devices and browsers.