Here is an idea: An announcement capability for sites. An admin should be able to create an announcement that displays on the site (every page?, just the front page?). Users should be able to dismiss the announcement. Admins should be able to clear the announcement or set a time for it to be removed.

+1 on the announcement feature.  I need this sort of thing fairly often.

Mike

If you're still taking suggestions -- followers/following widgets for this plugin:

https://github.com/ewinslow/elgg-followers