You need ten posts to use most of the features. There is sometimes a delay after you reach ten posts though. Give it an hour or so after you get to ten posts and you should be able to search your posts.
If you click on your profile you can do a search to find all your posts. Also, if you look at any of the boards you will notice a check mark next to any topic you have started or replied to. It looks like this [IMG]/justmommies/
vb/images/statusicon/thread_dot_new.gif[/IMG]. If you need any more help let me know.