The important point to note is this:
"GTA IV PC also requires a number of software installations, including Games For Windows, Adobe Flash, Internet Explorer, SecuROM and our Rockstar Games Social Club application."
For those of you who don't know how to interpret publisher jargon that should be read "GTA IV PC also requires you too introduce slow downs and insecurities to your computer"
Excuse the bad pun, but personally I don't think Rockstar has thought their game-plan through very well. They create a game themed towards GENERAL RULE BREAKING, SPECIFICALLY THEFT, and GETTTING AWAY WITH IT. Then they publish it at the largest and most resourcfull crowd of security breaking guru's around. They impliment security that this crowd will easily circumvent but which will annoy their legitimate users nearly too death. Then they idiotically show up on the news going "we just don't understand why people don't buy our games..."