ISPs block millions of legitimate emails

ISPs are blocking millions of legitimate emails a day as collateral damage in their war against spam, according to an email delivery company.

The worst hit are social networks. Friends Reunited, for example, had as many as 27% of its emails bulk blocked by ISPs in May, according to Return Path, which advises companies how to get messages through to end users.

We’re not talking about spam, these are emails that people have asked to receive

“About one in five commercial permission-based emails are being blocked globally, and 15% in Europe are blocked because ISPs are treating them as spam,” Margaret Farmakis, senior director of response consulting for Return Path, told PC Pro. "I wouldn’t be able to say if it was millions or billions, but it is countless.

“We’re not talking about spam, these are emails that people have asked to receive, but that are being treated like spam,” she said. “It doesn’t effect one-to-one emails, but a lot of marketing emails and communications from social networks, for example, are never delivered to the end user.”

According to Return Path, email is often caught in the spam trap because some end users flag emails as unsolicited when actually they have just got bored of receiving emails from a company. If a company receives too many spam reports – around 1% of mails from any one company – then all emails from that company are tarred with the same brush.

Social networks are increasingly falling into ISPs’ spam filters because of the way subscribers sign up to the services, with networks often suggesting that users import email address books.

Return Path said emails from social networks were twice as likely to be caught up in the ISP bulking traps than mails from other industries.

“The practice of importing loads of addresses can have an impact,” said Farmakis. “Effectively you are sending a lot of emails to people who haven’t asked for them, and some of those email addresses could be really old, which might be out of use or being used as spam traps. It can be risky.”

Despite the high number of false positives, Farmakis refused to blame ISPs for the wrongly blocked missives, saying that some legitimate emails were inevitably going to be caught in the crossfire.

“Between 97% and 98% of all email is spam,” she said. “ISPs have to weed through it and try and discover what they should deliver and when they should protect their end users from spam. It’s like they’re fishing and if a company’s email looks too much like spam they get caught up in the net.”