I've just uncovered a large number of hijacked member pages on an old community server site I have on a subdomain of my main site. The site is reasonably well indexed etc and has been ranking well for long tail searches for quite some time. However it looks like about a month ago a large number of automated registrations led to a few hundred pages being created with some, lets say "rude", content. These pages then linked out to some of the worst neighborhoods any sane/legit webmaster could imagine.
Unfortunately, this previously well-regarded subdomain is also linked to from all of my established family-friendly sites (the links have since been removed). Herein lies my concern: linking out to "bad neighborhoods" is pretty high on the list of potential SEO disasters - and by linking to this subdomain from my main sites, it looks like I have inadvertently been doing just that during this past month or so.
So... the subdomain has been taken down, and all links/connections from my main sites to the subdomain have been removed. However all these pages had been cached, indexed and were ranking in the SERPS, so now I'm nervous.
The point to all this?
1. A simple cautionary tale to make sure your member registrations are locked down - particularly if you are using CS, which appears to be the focus of a lot of spambot activity at the moment.
2. On my part I'm fishing for some feedback on how bad this can be for me. All of my main sites linked out to the subdomain that was compromised. Could I be facing certain death in the SERPs?