The community is at least one day, or it is updated for a long time. Considering the amount of spikes, in addition to a few places, it should be automatic update.
For example, a hot spot in 48 hours a new post.
The forum is a fact that is updated. Taking into account performance, his cache can only be 1 minute.
That is, the list of posts on the forum, caching can't be more than 1 minute.
