Suing the spammers vs suing the P2P software users...

Microsoft has been getting some more positive press lately for their attempts to help curb the amount of spam that gets send.

On the other hand, the RIAA typically gets negative press when they sue potential infringers.

My question is, in both cases it appears that having a "big" guy sue helps get result.

So why the different reactions?

I can see some differences, but I think that if the overall concept is that just because you are big isn't a reason why you should succeed, then we shouldn't be happy in both cases.