[clusmore]

I like Joel on Software's reading lists. Basically tags but only for a very small subset of posts which are very good, hand-curated with purpose.

As for "older posts may still updated", I suggest don't do this, unless your site really is more like a wiki than a blog. It's annoying for readers to have to reread old posts and try to spot the difference, it means they can't bookmark a post they like and send it to friends without fear it might change. It's annoying for you because you will end up obsessively trying to perfect old posts. I prefer the approach of just writing a new post if you think you have a substantial amount of new/different information to add, and then you can also show what changed and why. This also means you can go back through your archives and see how your thoughts have changed over time.