what they are doing?
 

recently, I setup a WPMU site, at day1, I am surprise I got 10+ user signup and start their blog...which sounds good....then, I find out they all come from same domain.(looks like one person)

I guess someone is testing some auto blogger tools, but anyone have same experiense and know what they are doing?

if they have links in post spamming it
if none just useless messages they're testing the security of your mu setup

they do have some links in a few blog...but most post just some artical....I don't know if they are doing anything wrong, as they even put their blog "un-visible" to public, which means only site admin or (I guess google spider) can read it...if my guess is correct, then, they seems expect this kind of thing can help their rank in google may be.....then, it is spam type of things

I had this same problem with an MU set-up - it's spam. They've got some kind of bot setting up multiple blogs and they ended up being filled with Viagra ads and the like. Very annoying.

If it comes from one domain, it must be spam powered by automatic robots. At times it may stay in your site inactive, but it may unleash havoc to your site later.

what I need to do then...? I googled that domain, get some item talking about similar thing regard them....I didn't block it yet, as so far they didn't hurt me....but any suggestion?

if you are worried about deleting a legit site email them and ask some questions if they don't answer just delete the blogs