Email is not direct mail

Had an interesting talk with a colleague at a BBQ this weekend. He was at a large ISP and then moved on to do delivery at a large email marketing company. This marketing company was started by a very successful direct (snail mail) marketer. The CEO believed totally in testing and they measured everything. They knew what colors provoked a better response and which fonts were better received by recipients.
But this wasn’t always enough. They had some spotty delivery and my friend was hired to try and solve the delivery problems. He had some luck and did fix a number of things, but there was a deeper issue he couldn’t address: that email is not direct mail. The types of testing done is the type of testing for direct mail. They were so focused on getting the best response to a particular offer they refused to consider tweaking an offer from their “proven ideal” to stop triggering content filters at some large ISPs. So their ideal offers would sometimes end up in the inbox and sometimes in the bulk folder and sometimes just disappear.
With direct mail, the USPS is required by law to deliver mail to the addressee. Not only that there are a lot of barriers put up to prevent (or discourage) recipients to opt-out of receiving direct mail. This isn’t the case in email. Not only is their no requirement for an ISP to deliver email to recipients, there is actually a law that says that recipients must be able to opt-out from receiving future emails.
Direct marketers are used to having a lot of freedom and control over their mail. They can buy and sell address lists and send almost anything they want without having anyone tell them they can’t. That mindset translates badly into the email space where the ISPs and the recipients have a lot of control over their incoming email. It means that senders with the absolute perfect test copy see delivery problems because their perfect copy looks just like something a spammer would do and gets caught in content filters. It means they come into email and try to buy a list and discover that while it may be financially viable, they have to deal with angry upstreams, blocks at recipient ISPs and sometimes a Spamhaus listing.
Email isn’t the same as direct mail and attempting to map direct mail techniques onto email usually doesn’t work.