When I search (by user) for posts that I KNOW are there, the search feature of this forum fails to find them. How come?
Search is working fine for me.
Are you sure you are using the right keywords?
Is the username spelled correctly?
Correctly selected match all words/match any words/match as frase?
Can you give an example?
Eddy,
Don’t wish to disagree with you, but my “search” does not work either. It never has. I can’t even find “me” ! ;D
Other searches work ok, but not when I search for a user post.
Got me puzzled.
This feature does not work all the times…
It’s erratic 
I participate in several fora that use the same software, but only in this one have I encountered the failure of searching for a USER post. I tried to use it in the most straightforward way: I typed “venik” and got no hits, even though I could find them by hand.
You need to enter a keyword also. Just the user name isn’t enough.
Hint: Use only the letter “e” as keyword will do ;D
If you are looking for posts from a user do it through their profile.
I fully agree with Eddy’s instructions. My isp uses a transparent proxy and sometimes fetches “stale” web pages, but the search function always works here although the results might not be completely up to date unless I manually force a page refresh.
Quick edit! “Always works for me” instead of always works here 
It works ok for me, providing as you put something in the Search For: window e as Eddy said, will be in every post. Then the only problem is getting the By User: (username) correct.
A case in point being Eddy, because that is his Screen Name and not his Username.
To find a correct username, you need to click on the screen name which will display the user profile, which will show the username for a search.
One advantage of opening the user profile is you can display the last n (n being a variable number you can select) posts by the person. So you may not need to do a search.
At the moment it works for me, but has been on and off in the past. Try to make your search more less specific.