i was on this music sharingsite, and this little window came up. it said trend smart and that this website may contain malicious software. but the problem is why does it say that? i thought macs were prone to viruses. what happens if i download a file with the most malicious softwatre??

Technically yes because it's a computer, but the reality is that there are no Mac OS X viruses in the wild. Some malware does exist; however, the malware requires user interaction to infect the computer.

There are currently at least 20 Malicious programs attacking Macs in the wild. Trend smart is a Trend Micro warning either from software you have installed locally, a router, or a service provided via your ISP. You are very unlikely to be impacted, but it is not impossible.

A virus will infect your computer without you knowing anything about it. There are no viruses that will infect Mac OS X. Malware is software that you have to actively install yourself. It is possible to install malware on a Mac. If your system software is up to date it will warn you if you are about to do this. The Trend Smart software, which has been installed on your Mac by someone, acts as a filter against dubious music sharing sites and provides some parental control over what sites are visited.

there are viruses for your precious little mac... even though they still are quite rare
but you need to be cautious anyways :S