I tried searching to see if anyone else has had this problem, but it seems my searchFu is lacking, or no one else has reported this problem on the forums. So, here it goes.
Whenever I try to use the automatic update feature (both for WordPress itself, and for any plugins), and when I try to install plugins from within WordPress itself, it opens the window where it tells me it's downloading the file, and then it just sits there. I've tried leaving it overnight, wondering if a slow internet connection were the problem. I've tried refreshing the page, assuming it had timed out.
Nothing seems to work.
Useful data: The blog is hosted via 1and1.com (not using the built-in 1&1 blog, but independently installed the files myself on my domain). - I was having a problem earlier with internal server errors and found the problem was specific to hosting with 1&1 via the forums here and I was able to fix it with the suggested solution.
I AM able to manual update, but the automatic features are so much more efficient and I often put off the manual updates because it's a little more time consuming and I just don't always have the time to do it when the new updates are first rolled out or when I'd like to install plugins.