Spam is a worse crime than murder. Big spammers like Ralsky send enough spam to waste many lifetimes' worth of people's time. Just because the damage is spread out over a large number of people doesn't make that fact any less heinous.

It all depends on the definition of the "spam".

I'm not referring to those blatant buy-a-mailing-list-and-spam kinda process. I'm talking about the more subtle invitation "spam" executed by the likes of plaxo, hi5 etc.

Like this?

http://blog.plaxo.com/archives/2005/12/

Doesn't sound like spam to me.

If I was trying to make a site that will last, then no, because I'd feel dirty -- and it's a dirty way to start out.