I went to send a private message on Twitter for the first time in probably 6+ years, and was made to do some human verification thing through a third party service. It said something like I had done something unusual, which I suppose is true for my account that I only really use for lurking and occasionally when my site goes down. I had to go through three side by side sets of images and find a number of icons on them that match the count in the other side. It went fast once I figured out how it works, but figuring it out took me a little bit, since I had never seen a captcha like that before.
Once I took the test and passed, it sent me to the home page. My message wasn’t sent, so I had to rewrite it and send again. It did send, but I’m never pleased when those sorts of things just get rid of what I was doing.