This https://genealogy.meta.stackexchange.com/a/3296/6485 suggestion seemed to slip through without being implemented -- should we take it forward?
online seems to be used for a grab-bag of purposes -- finding and relocating records online, publishing online including ethics questions, message boards, online tree software, synching online and offline trees...
Note: the tag has no wiki, so it's not surprising it's a grab bag.
Updated to add: I'll leave this here for a week to get reaction, and then act on the most upvoted answer.