Yeaman is correct about the size of our Network and there are lots of ways to improve your search results.
One of the best ways can be found here:Filtering Fakes From Search Results
You can also find better results by changing the key words your using to search, Sometimes WinMX finds more results if you dont limit your search too much.
For example if I wanted to find this title
RIAA Phone Call - The Mavis Beacon Mashup
I might want to limit my search to this
or Mavis Beacon
This would allow your search to be more broad and get you more results..