A It happens all too often: A Web search for an ancestor turns up a nugget of information on a message board, but when you try to contact the person—no dice.
First, check out the poster's user profile. If it includes a personal Web site, visit to look for updated contact information. If you're not that lucky, look next for a full name in the profile or the original posting.
You can then search for the name in an online directory such as Yahoo! People Search or Switchboard. Doing a Google search for the name may turn up some contact information as well, though this will be more helpful if you're looking for a Heidi Kryschek-Horowitz than if you're scouting a Steve Smith.
Another tactic is to search Google for the person's message board username—people often use the same ID on different sites. GenieFreak293 may show up with more-recent activity on other forums.
You can take this as a lesson in genealogical karma. Whenever you get a new e-mail address, always update your contact information on all the Web sites where you've posted queries. Or sign up for a free, Web-based e-mail account at Gmail or Yahoo! to use just for genealogy correspondence—then you'll never need to change your e-mail address.