I'm working on a site where you can email some customized site results. Our team has a theory that most of the time people who are using "email to a friend"-style functionality are actually emailing to themselves, however I can't find any data/studies to back that up. This would affect how we design our email form. I'm wondering if there is any research or proof out there that people primarily email pages to themselves?
I agree to your statement that it’s hard to find relevant data on your question. There are many opinions on what you’re asking, but very few answer. In addition, Yahoo! Answers aren’t valid in this context. That’s bad news.
However, there are good news too. Since this is “your” system, you can easy to check if you have signed in users, and e-mail is required. What you need to do is to compare the signed in users e-mail, compared to the e-mail to field in your applications e-mail page. It will not be 100 percent accurate, since users may use other e-mail addresses as well, but it would roughly give you a hint if it were 10 % or 90 % of your users mailing themselves.