The actual success rate(people buying something in response to the mail) of Spam Emails is really, really low. Its only profitable for Spammers because it costs pretty much nothing to send millions of emails. Now, if you actually paid someone to write these emails by hand, sure your response rate would be better but I seriously doubt the whole thing would still be profitable.
Also, I think that personalized adds and recommendations(Amazon,Google,Facebook,etc.) have a much higher success rate, simply because they have more information about you and can therefore recommend products that you are more likely to buy. Spammers could of course also collect information about you to personalize their Spam, but considering that most add/recommendation systems work automatically(and are pretty good), I don't think paying someone to create these recommendations would be worth the effort.
I've even received a (slightly) researched, personalised Powerpoint presentation from a company out of the blue. I didn't buy, but interestingly I also didn't mind. Perhaps this is because I felt that it may have taken longer to create then it did for me to discard it.
My biggest objection to a whitelist-only system is that although emails out of the blue are very rare, they are also far more valuable than regular emails that I receive. Given my reaction above, I'd prefer a proof-of-work requirement over a blanket block. This still presents an undesirable requirement on the sender, but it would be better than a block.
I get these from time to time on my professional email address. It's a soft form of a cold call & often contains information pertinent to what you are actually doing. Somehow it creeps me out that somewhere, someone is paid to produce these ppts. en masse. This is a job that deserves to be outsourced, yet most of the time they seem to be produced by cog21@majorcorp.com
People would still report these emails as spam, and the sender IP address or email address or domains or urls would still get added to block lists.
"personalised spam would be unfilterable" assumes that systems only filter spam on the text content. Much more spam filtering happens purely on IP addresses and domain names.
I pointed this out in an earlier discussion, but the difference between spam and ham is only that the value of the information in spam emails is very low.
Now it would be possible to increase the value of the messages to some degree, but the problem is that most of these offers are for medication that doesn't work to solve issues you don't have -- and therefore the maximum value of that is nothing, at best.
The only way to make spam worth more is to not sell scams, but sell goods that are actually worth something, in a way that the recipient values. A great example of this is the John Cleese Compaq ads (http://www.youtube.com/watch?v=RlmzwZXa-Ww) which adds value to the company and the user.
Also, I think that personalized adds and recommendations(Amazon,Google,Facebook,etc.) have a much higher success rate, simply because they have more information about you and can therefore recommend products that you are more likely to buy. Spammers could of course also collect information about you to personalize their Spam, but considering that most add/recommendation systems work automatically(and are pretty good), I don't think paying someone to create these recommendations would be worth the effort.