Becareful of the file sizes that you download as they can contain viruses/trojans, even on a Mac. I suggest you run an AV scanner each time you log off Limewire. File extensions to download for mac's on Gnutella are the sit files, Im not sure about the other extensions. Software is extremely large, depending on what it is and sometimes the sit files are all in one. you shouldnt get links to porn. That is spam and junk files, beware because those will harm your computer.