Reconnecting with people

These are the two most well known sites because they advertise heavily (and in my experience) deceptively.
Even from just a practical viewpoint, because they charge for "subscriptions", very few who register maintain their paid subscriptions and so you will have difficulty contacting anyone. Further, just by viewing those who have registered in the past, will often result in them getting a email that "someone is looking for them" when in fact you may have no interest at all in contacting them, but the email will do its best to entice them to resubscribe to satisfy their curiosity.

Good

• ClassReport.org

ClassReport.org does not require payments. They actively encourage donations, but promise to never require them. There are usually enough classmates in an active class that are willing to donate, so that the website should remain viable well into the future. Unlike the other sites, admins are allowed to administrate a wide variety of material for each class, as well as providing tools for managing reunions and other events. This can result in some very interactive, communities of re-uniting classmates. For example, see this class page or this one.

Other social networking sites:

• Facebook.com
• MySpace.com
• LinkedIn.com
• etc.

Even if the person you're looking for isn't a user on these services, their children or other relatives might be. On Facebook, for example, search using the surname and the hometown as keys. If the surname isn't too common and the hometown isn't too big, you might find someone who knows them.

Online vital records

• SSDI (Social Security Death Index)
• Obits (Google the name with the word "Obit")
  

(this Knol is still under construction)