I've decided that once I get an idea for a blog post, I should just type it up and push it out like I'm aggressive mom-to-be past the due date and I just want it all to be over (angry comments soon?).
Rule: If you are writing something - anything - online and you want it to be useful, one of the most basic things you can do is include the date. Yes, there was an article without a date and it annoyed me so much that I had to write a rule about it. There was also the time when I got excited about a band coming into my town... two years ago. Well that would be awesome if I had a frickin' TARDIS, but I DON'T! (ooh, watch my page hits increase now)
See here's the deal: you are on the internet. Ideas are flying around all the time. There are all sorts of cross-references. New technology/software comes out. Things are moving so fast, that yes, something you posted two months ago could become mildly irrelevant (or really irrelevant). I'm sorry if that scares you; that's what it means to be on the internet. But guess what! What's helpful to your readership (and folks using search engines) is a DATE! If I look up the top 10 iPhone photo applications, I want to know they're the top 10 RIGHT NOW. Not the top 10 applications that are now seen as feature-poor, sad pandas.
You think you can hide the irrelevance by hiding the date? Nope. What if somebody wants to give a "history of iPhone photo applications?" Your easily-searched site without a date could easily have been a good reference point, but nope, no date, so you've eliminated THAT use for your page too.
Please. Please, just include a date with your postings, folks. It doesn't hurt anything, and adds so much value to the reader. Even if they can't appreciate it consciously/immediately, they will once they look for it.
Also in other news, I've had a bout of inspired, productivity/self-improvement fever. In this regard, Ze Frank is still relevant even from 2006 (and just pretty damn amusing):
Psst... this is another example where including the date is good. If you're still relevant years later, it can only be impressive to see the date.