Ever fail to receive a reply on an email? Could be that your recipient isn't ignoring you, after all; if they're a Verizon customer, it could be aggressive spam controls. According to email software vendor Sendmail, spam-fighting has "in some cases eroded the reliability of the mail system. Now a lot of mail gets filtered out."

Studies from Ferris Research indicate that an average email user might lose between one message a month and five messages a week, ending up in junk folders or being rejected outright by the provider.

Verizon has been blamed for most of the problems, and the company has even been accused of denying all emails from certain countries, outright (although they've denied these claims). Five Verizon customers in Los Angeles have filed a lawsuit against the company, and a Philadelphia law firm is asking for arbitration to settle its claim that Verizon has caused it to lose potential clients.