Wired: When Everything Was Spam to ISP

For email marketers it is getting increasingly difficult to get messages through. What they don't expect however is for an ISP to start bouncing legitimate email:

An overly-sensitive spam filter is to blame for a week-long blockade that resulted in nondelivery of some e-mail messages sent to EarthLink subscribers in late October.

Whilst Earthlink has rectified the problem, many think that this is simply a sign of what's to come, with mail filters set to become increasingly zealous.