Comment spam getting smarter and Drupal-focused

On various of my sites I have seen an increase of “smart spam”. Spam aimed, so it seems, specifically at Drupal sites.

One of the most annoying tricks is the duplication. A bot grabs an existing comment, and posts that again, this time with its own link. The Drupal Spam module catches these too, but it also un-trains the spamfilter. The increase of these re-postings has a negative effect on the spam-tokens: I have seen a lot more correct comments end up in the spam queue lately.

I fear the worst. I fear that a large part of the increased online communication will be smothered by spam soon. The continuous battle against spam will tire a lot of people so much, that they will simply stop being part of that online community. Only a small percentage of the website owners can afford the budget to keep up top date with the latest spam-fight techniques.

I expect most the captcha systems to be cracked very soon too, rendering that useless too. If you see the amount of effort put into spam techniques, we can be certain that a lot of budget is available for captcha-cracking.

Centralised White- and blacklists (like akismet) may still work for personal use, the basic concept is rather flawed: who knows what happens to your valuable comments when they pass into the database of akismet? Spam filters have become less and less effective, captcha helps only in certain areas, etceteras.

Are there any other interesting ideas and concepts to fight online spam? Is there some technique I missed that may help? Would a decentralized, Open, akismet –Open Spam Tokens– provide a real solution?