You can do what I do: http://www.gwern.net/Archiving%20URLs
High startup cost, but on the plus side, you don't need to do anything once it's running and it'll catch most of what you read.
OT (except that I ran into this while visiting that page): That Beeline thing is really annoying. (I got the "blues" variant. I was annoyed enough by it that I modified the cookie to serve me a different version. I asked it for variant 3 ("gray1") and actually it doesn't appear to be doing anything; maybe that's a bug somewhere. Anyway, my apologies if this introduces noise into your A/B/.../I testing.)
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.