@ suggestions in extension should be more than just followees

[amyxzhang]

only show suggested followees when there are more 5.

if there are < 5 suggestions or something, start showing people who have posted on the bulletin already.

useful when wanting to reply @ someone who has commented on the bulletin but you aren't following them. right now you can just type it in, but maybe it should be suggested too.

Then maybe below that, strangers sorted by decreasing followee count (too noisy?)