So your friend invited you to join LinkedIn, and you signed up. Now what?
Answer: find out which of your friends and colleagues are already signed up. Here’s how to do it.
1. Export your contacts from your e-mail programs, into comma-delimited files. You can do this whether you use Outlook, Lotus Notes, Thunderbird, or any of the popular online e-mail services such as Yahoo, Hotmail, Gmail, and so on.
2. Import your contacts from these comma-delimited files into LinkedIn. To do this, log into LinkedIn and click My Contacts > Other Contacts > Add More Contacts > Other Address Book. That will put you on the Upload Your Contacts File page. Click Browse and select the files you created in step 1 (you’ll have to repeat this procedure for each file you created).
3. LinkedIn will then give you an opportunity to automatically send a LinkedIn invite to each of your contacts that are already LinkedIn members. Chances are, most of your colleagues who use LinkedIn already will readily accept your invitation.
This will give you a great jumpstart for adding people you are connected to via LinkedIn.