Quercia and his colleagues analysed the dynamics of more than 34,000 Facebook relationships to find patterns that correlated with unfriending. He presented the results at the Web Science conference in Evanston, Illinois, last month.
Sure enough, a lack of similarity, especially between ages, and few mutual friendships were the dominant factors correlating with unfriending - all of which mirrors the decline of physical-world relationships. Quercia also found that having a mutual female friend makes unfriending less likely than sharing a male friend. Clues as to why come from research conducted by Robert Bell in the 1980s on gender roles in friendship. In short, Bell showed that women tend to form deeper, stronger friendships, and they strengthen relationships beyond their direct ties in their social network.