My kids love watching videos on YouTube and now that my daughter has learned how to read, I worry about the words she may encounter in the comments section below a video she's watching. Thankfully, I found a Chrome extension, YouTube Options for Google Chrome, which lets me tweak the appearance of the video player page on YouTube.
After installing the extension, a small icon shows up on the right edge of your URL bar when you view a YouTube video. (It's a small red button with the letters YTO.) Click on it and a narrow window opens below it with a small, sample YouTube page. You can click on the various components of the page -- header, title, description, comments, suggested videos, footer, playlist -- to toggle between hiding and showing them. You can also adjust the size of the video player, and if you click the Options link at the bottom of this window, you'll be taken to the extension's settings page where you can tweak further options. The extension remembers your preferences for subsequent visits.
In related news, you can replace YouTube comments with Facebook comments with another Chrome extension.