Finding multi-word trends from a pool of full text columns

Finding multi-word trends from a pool of full text columns

In my app users can post statuses similar to facebook. They can also use
hashtags which i currently use to figure out whats trending locally, but
as you can imagine not all users always use a hashtag when posting about a
trending topic and not all trending topics are a single word.
Im currently storing all user statuses in a fulltext column in my db and I
have querys that pull all statuses posted within 20 miles in the last 3
days , but now im wondering what is the best way to go about figuring out
whats words/phrases are trending in that set of data? I realize this
question is kind of broad/ambiguous , but please realize this is done
purposely because I really have no idea what the best way of going about
this is. If I can do it using pure MySql thats great , but if there is a
much better way of doing it using PHP , a existing(php/java) library built
just for this purpose or a API that might help with this then im open to
hearing about it.
Ive noticed there is a serious lack of quality posts on this topic both on
Stack & around the web so please if you have any ideas or suggestions
regarding this topic dont hold back. I really feel we need a good thread
on this topic.