New user Tipota (now Vergil exe) has recently posted a series of spammy comments on a draft thread:
Also of note is that it took them some time to figure out how the sandbox worked, evidenced by this comment chain on the SCP announcements page and this thread that apparently demonstrates that they ignored a staff comment from Crayne.
Edit: And they've pulled the "make a thread, get not-positive feedback, delete draft" ploy twice, even after Crayne cleaned up after them.
http://www.scp-wiki.net/forum/t-1155432/null
http://www.scp-wiki.net/forum/t-1155636/mr-mayo
Keep an eye on them.