Most users ever online was 1,830, 06-21-07 at 04:04 PM. aRszRc, bNlrXv, bYwcLb, hYhjBc, jBwsJe, vChjSm, wTizEc, yJpiCi Whee... Interesting to note that all the jibberish spammers all have a lower case first letter, then an upper case, then two lower case, an upper case, and they all finish with a lower case. Random, but symmetrical in pattern. They all coming from the same IP?
To be honest it looks like a "botnet" attack. This sort of attack is usually done to circumnavigate flood controls by coming from more than one IP. I would suggest if any Sciforums members have received PM's from new users that they weren't expecting not to follow any of the URL's that are given. (There are a number of playloads that might be forced on you otherwise)