"Oh wow, didn't think of the stalking issue.
Well how does classmates.com prevent that? "
Probably the most effective prevention it uses is the cost. If you become a member and join (which is not cheap) and continue to pay your annual dues (ditto), you can send email to anyone who is registered. If you haven't paid up, you can't, but you can be a registrant.
Classmates.com does now provide separate forum for meeting up with previous co-workers, as well as any school alumni(ae), including nursing schools.
Further, the way it seems to work as best I can figure it out is that registrants can not send you email back if you are a member and send them email, unless THEY also join and pay. People do not list their present locations, phone numbers, or addresses on classmates.com unless they happen to wish to include a link to their personal web page, where they may include this information (not a good idea, regardless).
The main reason for this, no doubt, is that classmates doesn't want registrants to circumvent their $$$$ machine in order to establish an ongoing relationship with other registrants and/or members without paying the site first.
On allnurses.com, so long as people don't put personal information in their posts or in their profiles, they can be PM'd or emailed (if they wish), but others can't locate them physically. the same way it is now.
My main concern would be correlating usernames with real names--which would discourage frank posts, so common sense guidelines might be provided for people who might not think about that when listing themselves for peer to contact.