While we've been saying a lot of the same stuff for the past six years, what's changed is that more of the right people are finally listening. Six years ago, most major media coverage about spam still summed it up as opt-in vs. opt-out -- if they were even savvy enough for that. Six years ago, the FTC's policy was (or seemed to be) "hands off the Internet." And six years ago, none of the big industry players were issuing joint press releases about spam.
But your question was about what we've learned, and I think that what we've learned is how to work with all of the marketers, lawyers, politicians, and other non-geeks that we have to share the Internet with these days. We've learned how to explain things in terms that average folks can understand, rather than ranting and screaming and scaring them off.
Some of us already knew those things to one extent or another, and there are still others who will read this and scoff and go back into their walled gardens. On the whole, however, I think that the relatively sane arm of the larger anti-spam community has become much more effective.
We're winning, now, slowly but surely.
