MailChimp is the service I use for my newsletter. Yesterday they rolled out a new service that allows publishers to easily find other publishers for potential strategic alliances, co-marketing, etc. While it seems like an awesome potential, this service would violate my own policy of sharing contact information with other parties – something you might want to consider.
Finally, we have all the pieces we need to build Wavelength: a MailChimp service that uses a massive amount of email data to help you find publishers who share something in common with you:
Basically, Wavelength analyzes your MailChimp list, then compares it to all other MailChimp lists (really, really fast). It looks for subscriber overlap, then recommends similar publishers by showing you screenshots of the email campaigns they’ve sent.