GenCircles

GenCircles - http://www.gencircles.com - is a site where individuals can enter their relatives' details and find links to others.

The focus of this site has been said to be on family lineages. One of its features is "smartmatching", giving you a list of other genealogies on the site where an apparent match is found.

As with a number of sites, there are:
 * a free option, and
 * some better options involving payment.