Until today, I had no idea Yahoo Messenger even existed. But it most certainly exists, and if you happen to use it, you might be excited to learn you can now send video. The iOS and Android apps now support sending video, up to one minute long, in both one-on-one and group conversations.
Yahoo Messenger is pretty much your average messaging client, but there are some neat features. You can "unsend" messages and media in a conversation, it supports Google TalkBack, and there's even a native client for Windows and Mac. Which Hangouts still doesn't have, after all these years.