From eMarketer:
"A Rapleaf study of 30 million social network users worldwide found that women generally have more friends on social networks than men."
80% of users interviewed had betweetn 0 and 100 friends on social networks. Women averaged 62 friends, while men averaged 57.
Among respondents with 100 to 1,000 friends (19% of the sample), women averaged 185 friends, while men averaged 172.
Rapleaf suggests that "women spend more time on social networks building and nurturing relationships, while men are more focused on acquiring relationships from a transactional point of view."
I think I agree. This goes back to how men and women view friendship. Guys can go months without talking to friends (we don't like long phone conversations) and then pick up right where we left off when we hang out. Girls seem to feel the need for more regular dialogue and keeping in touch with their friends, in order to consider them to be good friends. Then again, maybe these are just stereotypes...
From what I've noticed on Facebook, girls who are friends tend to post on each other's walls and comment on pictures and videos much more often than guys do. Twitter is a whole different story though; I'll interact more with people there (and people who I don't really know as well in "real life."). I'm curious to know if this is similar or different to your own experiences with your friends on social networks.