One anti-spam service I tried a few months back was Melbourne-based Aliencamel, which I thought was good but not perfect, have just announced some new features which may make the product more competitive in a tight marketplace. Aliencamel works as a mix of different anti-spam and anti-virus elements designed to keep out the riff-raff so you only download what you want.
The new version turns Aliencamel into a kind of email account in its own right, including the ability to preview email in a web browser before tagging it as spam or downloading via your normal email program, full webmail access to your mailbox, as well as disposable email addresses you can use to deal with suspect web sites and third parties you’re not sure about. On top of that the service’s Pending Email Advisory — a sort of floating alert that lets you know of new email that is suspect without actually sending it to you — changes to reduce frequency of advisory emails.
Most important, I think, is the fact that Aliencamel are going to embrace Bayesian filters — the simple method of assigning a probability of spamminess to emails by looking at the innards of the email (content, header, HTML code) and comparing it to other emails it has looked at. I adore Bayesian filters (I still use POPFile) so I think it’s great that Aliencamel are moving in that direction.
(Aliencamel, by the way, is an anagram of clean email. It took me months to get it.)