CNET had this piece on a recent email survey out of the Bay Area: E-mail and its discontents.
Unfortunately, they miss on a point or two, so Spamroll will help them out.
First, one-third of respondents DID NOT say they used Gmail. Roughly one-third of respondent who ACTUALLY USED webmail, said they used Gmail. And those who USED WEBMAIL represented one-third of total respondents for personal mail, and roughly one-seventh for work, to begin with. So Gmail usage is much lower, in percentage terms, than previously suggested.
Second, while roughly half the folks polled admitted to keeping more than 50 emails in their inbox, I was actually surprised to see that more than 70% of respondents admit to archiving old email.
Anyway, for the complete survey, check here: ClearContext 2005 Email Usage Survey Overview