It does work if you try hard enough - you may have to reset the search parameters to include titles as well as messages - but just found this post by searching for 'title' - answer is to change the 'Subject' in the 'Post Reply' either when posting, or by going back into the post and using 'Modify' - try searching for 'Newtitleforpost' (as above) when you find it you will have cracked it!!!!
If the person posting, or someone answering, doesn't change the title, you can always bookmark the post by adding your own title and comment if you think that you may want to refer back to it at a later date.... Just as I am doing/have done...