So yes, I’m aware and taken care of; Adblock Plus and NoScript in Firefox, all for free.

Yes, viruses–specifically, cross-site scripting (XSS) and SQL injection. Are these good reasons to block social networking sites? Maybe not (we don’t). However, if you’re going to be recommending these sites, you should at least have a minimal awareness of some of the issues libraries might face.

“Local law enforcement officers report that such sites are used to coordinate gang activity.”

Any more or less so than, what, /the entire bloody web or any other particular internet protocol application?/

“Network security experts say the sites are becoming prime targets for malicious hackers.”

Which? Where? How much more so that any /other/ sort of site?

I’d love to see actual citations of this research.

Unless this is just a really fancy, mis-directionally-advanced way of saying they’d like to keep the riff-raff out of their library.

“He said public library systems don’t have the money and resources to install and monitor anti-virus and firewall systems that would adequately protect their computers.”

Then they either don’t belong on the internet, or haven’t heard of open source (even for Windows anti-virus)? *cough* http://www.edubuntu.org/ *cough*