I've never been contacted by anyone actually related to me through GR, but in researching the trees of two friends lately I've had staggering success. For friend "M" I found 3 people related to her, one of whom had done the research right back to the 16th century on a couple of lines. For friend "G" I have, in less than a week, found 3 of her distant cousins, with information I didn't have, though without having got any further back. The point is that when a site like GR is genuinely useful and popular it attracts more and more people and so the connections proliferate. If we could persuade everybody with a family tree to put it on a single site, how easy it would be - but it would probably take the fun out of it.