Nothing "free" is ever really free, and "free" file-sharing services aren't either. They deliver adware / spyware to your computersExcept for the open-source ones that either don't have any adware/spyware, or you can remove the hooks yourself.
Typo:
The risk of sexual harassment suits resulting from employees downloading pornography is well know.Should be "known".
Personally, I don't trust software firewalls (Norton and the like) because I see no reason why a trojan program, working from within, can't disable or bypass them.By software firewall, do you mean software installed on each system? Or do you mean software running on a dedicated computer acting as a router/firewall? I suspect you mean the former, but as written it looks like you're saying that a general-purpose computer configured as a dedicated firewall isn't as effective as a single-purpose firewall box. I'm not a network security guy, but that doesn't sound right to me.
Another typo (or is this a style issue?):
Napster's users had no thought whatever but to amass vast amounts of top artist's musicThe way I learned it, that should be "top artists' music".