The (sponsored result) results are basically nothing to worry about.
The ones you should worry about are the results that match your search criteria exactly.
I.e. you search for:
Title: Tripping
Artist: Robbie Williams
and LimeWire turns up with a result exactly matching your title and artist and the file is usually 134,4 KB.
This is a virus containing a Trojan Horse and God knows what else.

Do NOT, I repeat, Do NOT download these files.
If you do not have any anti-virussoftware your computer WILL get infected with spyware and/or one or more virusses.
I'm running Norton Internet Security 2005, which detects the virus and won't let you open it.

If any of the moderator's reads this Topic, please contact any Limewire official who may be able to change the program to filter out these files or filesizes.

Obviously, LimeWire could impossibly be kept virus-free and therefore downloading is at your own risk.