The new thing all the "cool" social media spammers are doing now is impersonating famous people on twitter. They sign up for a name that is very similar to a well known person (ie "mattcutts" becomes "mattcutts_" and then sets their screen name to the exact name of the person they are impersonating: "Matt Cutts". I use Matt as an example here because it happened to him recently by a particularly clueless twitspammer.
They then "follow" a few thousand people, most of which are honored to have such a famous person following them, and thus go visit the person's profile to follow back. At this point you'll typically see only one or two posts, always to some sort of spam. Ironically, the one I've seen most is a link to a "whitepaper" on how to market your crap in Twitter.
So they spam you on Twitter in order to promote a paper on how to spam people on Twitter. Ugh.
To their credit, Twitter is usually pretty good at finding and removing these, but they are usually up for several hours and get a few thousand visits before they go down - enough, apparently, for some twitspammers to feel it's worth it.
The really scary thing (to me) is how many people fall for this, and start following back. Yikes! Hey, I've got $78Million I stole from the Nigerian government that I'd like you to help me get out - how about it? You can by that swampland in Florida, the Brooklyn Bridge, and still have some left over to invest in Bre-X!
ADDED: Andrew Girdwood posted about this earlier, as well.