Wayne that page is doing a full table scan on thread table so you might want to add an index on
postuserid
SELECT COUNT(*) AS started FROM thread WHERE postuserid=5584
Also this query is a bit painful but it is because you have 3360 posts (I assume) and will generally be more tolerable for most other users.
Code:
Query: SELECT thread.title,thread.threadid,thread.forumid,postid,post.dateline,pagetext FROM post,thread WHERE thread.threadid=post.threadid AND post.userid=5584 ORDER BY post.dateline DESC
Time before: 0.19469499588013
Time after: 0.53944802284241
I only mention this because there is a noticeable lagtime on that page.