Old study, but still interesting, from Social Media Explorer:

• People still share via email and instant messenger more than via social networks. An astounding 59% of all shares on the widget were done via email, 25% via instant messenger and just 14% were passed along on networks like Facebook and Twitter.
• Twitter, which has recently emerged as the share site du jour for those in the social media world, accounts for only one percent of all shares. Facebook is 11%. Yahoo mail is the highest individual share channel at 26%.
• Yahoo (44%) and MSN (25%) mail are way ahead of Gmail (19%) as the email provider used by Tell-A-Friend users.
• Facebook accounts for 79% of all shares via social networks. MySpace is second at 15%. Twitter is just 5% of all social network shares via the widget.

Thoughts?