Unless you’ve created your own social networking site (complete with html and all that fun stuff), I don’t think it belongs on your resume. I think if it was on there, I would wonder about your other competencies, as I don’t know anyone who is unskilled at social networking. If that’s the best thing you can say about yourself, you aren’t going to get the job.

Historically, would you have put ’socializing’ on your resume? Would you put ‘talking on the phone’ or ‘writing letters’ on your resume? The only place this might belong is in a section called ‘interests,’ but I don’t think that section belongs on a resume in the first place.