Thanks, enlightening text. I think, the biggest problems w/ blocklists are "guilt by association" (you lose all your connections because someone on your server was being problematic - I feel oftentimes account-based blocking should be the first choice) and these lists being created and maintained by a small group of people who are all more or less friends. On the other hand - as you pointed out - for now, they seem the most feasible option to provide at least some kind of protection. Not sure, if there will ever be a solution that fits all. Probably not.