One of the things that you learn when you have a blog is the permanence of things that you've written. You also learn that what you think is important may not mesh with what other people think. Where am I going with this?
Well, I wander through my referer list every day, and - other than adding spam sites to the blacklist - notice which posts keep getting referenced. Here's an example - I posted on the illogical pride that people take in being innumerate awhile back, and now I see a referal from innumeracy.com just about every day. Which I find interesting, because it's not a topic I write about all that often. I still feel strongly about that, but it's not something I focus on... and yet, there it is.
And that's one of the things you learn as you continue to roll posts out over time. It's a permanent record of sorts - even if the urls change or the site goes down, those posts exist in various caches (Google, Feedster, etc) - and will be there for a long time. Which brings something to mind - young people who've started a blog may well find posts coming back to haunt them decades later. Just think about the current Supreme Court hearings on John Roberts (regardless of where you stand on it) - there's been a scramble for everything he's ever written, in an attempt to parse his future thinking. Now, imagine it's 20 years from now, and a person in the same situation had a blog.
It reminds me of a book I read a few years ago, "The Truth Machine". Part of the scenario laid out in that book was archival recording of just about every moment of daily life. It had some fascinating consequences, and I'd recommend the book highly. To a limited extent, the archived posts being put up by so many of us are becoming that scenario.