E-mail chain letters travel much more circuitous routes to reach recipients than previously thought, according to new research funded by the National Science Foundation , Google, Yahoo and the MacArthur Foundation.

Jon Kleinberg of Cornell University and David Liben-Nowell of Carleton College say the messages don’t tend to travel so much in a viral pattern (you get a message, pass it to someone you know, they pass it to someone they know, and so on). Rather, initial recipients are seen as being pretty selective about where they forward messages, often only forwarding to one person.

The researchers examined two e-mail petitions that have swamped inboxes, one in support of public radio began circulating in 1995 (316 copies were found with more than 13,000 signatures) and the other slamming the U.S. invasion of Iraq, which originated in 2002 (637 copies were found, with about 20,000 signatures). The photo to the left shows how the researchers used tree diagrams to examine the path of email chain letters across the Internet.

One surprising finding was that messages often took meandering routes between people who knew each other, often through as many as 100 intermediaries. Many email users also received copies from multiple social groups. The researchers concluded that because messages come from many directions, there’s ample opportunity for the messages to be edited along the way.

"All of this adds up," Kleinberg says, "to cause a much more complex picture of how this information flows though social networks."

If you have saved a copy of either of the emails they are examining, they researchers would love for you to contact them at http://petitions.cs.cornell.edu/.

 (Photo credit: Jason Koski/Cornell University Photography)