[MySql] sort by frenquency

i’m a bit new to mysql, searched the net, but could really find anything:
I’ve got a table with 3 fields: “id”, “title” and “userid”. Someone can post a title and then his username and the tile are added to the table. What I want to do now is print the titles sorted by frequency of occurrance.

It seems to me you have to use subqueries to solve this problem.

Thanks