History of this site
See "History of This Website".
Update dates
When I make non-negligible revisions to an article (such as changing a whole paragraph rather than just fixing some typos), I change the "Last nontrivial update" date at the top of the article. This date only means that I've made some edit or other to the article. Sadly, it doesn't mean that I've reread the entire article to make sure the information is all up-to-date as of that date, since that would take way too much time. So recently updated pieces may still contain some outdated information.
Blog comments
Several people have asked me why I don't enable comments on this site. Before I moved to WordPress, part of the reason was technical: I wrote the site in a text editor by hand and didn't want to figure out how to manually add a commenting system. Now that I'm using WordPress, it would be easy to enable comments. I still prefer not to, partly for a selfish reason: Doing so would make this site look more like a blog and less like an academic website, and people tend to give less credibility to blogs.
Another main reason is that I feel bad about not replying to comments, and if I enabled comments here, I'd have more comments I'd feel obligated to reply to, even when I'm too busy to reply.
I prefer to incorporate feedback into the original piece and acknowledge people for their contributions, similar to what's done during peer review of an academic paper. Of course, enabling comments wouldn't prevent me from doing this, and I don't incorporate most feedback that I get into the pieces themselves.
Finally, a lot of discussion of my pieces happens on Facebook, Reddit, or other places, which makes on-blog comments less crucial.
No site ads
When I first created my website in 2006, I contemplated the idea of including ads in order to generate some revenue that I could donate. However, I leaned against it. Looking back, I now think it's obvious that adding ads would have been a bad decision.
The income from ads is generally minuscule, but ads cause a huge reduction in the perceived quality of a website, especially a non-famous one. Readers may associate ad-filled websites with spam and content farms, and ads may make it look like the site's primary aim is to bring in money rather than to provide information.
Plus, insofar as many of my readers are altruistic themselves, I don't want them to waste their money buying products after seeing ads on my site. Increasingly, there's also a risk of malvertising.