So that I won't be accused of failling to mention it, a UI change made today was to surround the list of sticky threads with a thin box to separate them from the regular threads a bit more.
However, in doing so, I came to a realization as to something I want to say in this post: A lot of the small UI changes I make, such as this one, revolve around A/B testing different things and then tracking statistics to see if usability has increased or decreased as a result. In these cases, beta sites just wouldn't work, as I need sample sizes of 1,000,000+ people in order to get an accurate overall representation.
This is very similar to what companies like Google do when they change their logo to be Goooooooooogle instead to see if it gets more/fewer clicks, and change color elements on their site.
However, for all of the bigger things, a summary of what's changed over the course of the month is always mentioned in the monthly newsletters.