When talking about the downside of making a YouTube video the biggest is that when you do this you are sharing it with the people around the world. The one mistake people make is thinking that the video will only be seen by members of YouTube.
You do not need to have a YouTube account to view videos. YouTube videos are emailed all the time utilizing video links to family, and friends. Now that you are aware that any video you upload to YouTube can be viewed by anyone with an internet connection, you may want to think twice about the information that you disclose.
For example if you are doing a video blog you may not want to put your real name, or your entire legal name. If you indicate what state you are from do not disclose the town, or city that you currently live in.
Sometimes you will receive personal messages asking you for personal information it is important to refrain from giving out this information.