How to publish comments feeds for your blog without going bankrupt
Last year, I posted a few times regarding short-lived feeds and the problems caused by feed readers that continue to poll them long after they've gone quiet. The issue came up again on Tim Bray's blog 3 days ago after he posted about his experience with enabling comments on his blog.
I just discovered Sam Ruby's entry on the issue from back in April (...not sure how I missed it then). His approach is to delete the comments feed after 90 days of inactivity and mark it with a 410 (Gone). Given that the comments still appear on his blog after the comment feed is gone (so the data isn't lost), and given that the primary purpose of the feed was to enable subscription to a frequently updated resource, there's not much to complain about in that approach (...not much anyway). The only non-trivial thing that I can think of that gets lost is the machine-readable metadata about each comment. I'll have to implement something similar if I ever get the free time.