You're both right that it is very subjective but I don't think the difficulty would necessarily outweigh the benefit or that it even has to be so hard at first. The list does not have to be set in stone. It doesn't have to be perfect. I don't think anyone could realistically expect it to be. It can and should be fluid.

Even if there was a list that everyone could contribute and argue over that in and of itself would make for a good discussion. My concern is for posts like Brian's that either don't fit in to a given category or have drifted off a category's main page become tough to find.(Posts we may not know to look for — if that makes sense.) Maybe it does make for a better incentive to visit individual profiles and that's great. If this took away from exploring profiles it would certainly be a big downside. (IMO)

However, I don't see the harm in trying if enough people would find it useful. If it fails it fails. But to at least begin by asking: "What's a good Perl insight?" I'd love to know what other people think the answer to that question is and see if we can apply it to posts we feel meet that criteria.