Creating hundreds of sockpuppet accounts to simulate active life on the site is pretty much standard industry practice,

I have been unable to find folks who'll verify this for me. I'm pretty well-read on Internet startups, and I've never found a serious source suggesting it.

Myspace got its startup push from a huge spam emailing

This InformationWeek article cites Sanford Wallace as the source of this rumor, and I was unable to find anyone else claming this happened. Given his reputation, I seriously doubt this is true.