What is a linked contact on a Google phone?

I just got the Samsung Captivate and it is the Google phone. Under contacts I have a whole slew of people (most with just emails) who some how popped up under "linked" contacts. What does "linked" mean in this case? What can be done with linked contacts?|||I believe those are contacts that you had on your email, that transferred over to the phone. A lot of sites can link contacts with one another, so you know who is on both sites. I assume that would be the same case with your phone, hopefully that helped a bit!