Just for those who make sro vids. YouTube just added a neat feature allowing users to add and remove text squares, bubbles and highlight squares where ever and whenever they want.
Example: (tested it on an old vid)
http://www.youtube.com/watch?v=h3deB5bfH54(ex. Time:05.50)
If a video has got these things, it will say "this video has
annotations" below it.