I have been on YouTube before just browsing through to see what I could find. Because there is so much there, it is easy to get carried away with time. One topic search could lead to another and, before you know it, an hour has slipped by.
I think people like it because it is so natural. The video clips run a range of topics both home-made to otherwise. It shows a cross-section of human nature. People are experiencing both the good, the bad, and sometimes the ugly. Some videos provide surprises; others showcase real tragedies. It is this surprise yet natural element that appeals to people. YouTube reminds me of a TV show from years gone by. It was called Candid Camera; it was an instant hit because the videos caught people in the act of life usually humorous, and people enjoyed the opportunity to laugh at the unexpected. In some way, YouTube is like that. It is a bit like reality TV.
Some more thoughts: Some video clips on YouTube are rather gruesome and distasteful. I am wondering how much of these have been staged. Saw one where a young East Indian baby who was crawling was being attacked time and again by a cobra and the child seemed to be okay. In fact, he actually reached out and touched the snake before it recoiled and struck him again in the head. How accurate are some of these clips? I guess some people gravitate to YouTube for some of this sensationalism. Reminds me of Ripley's Believe It or Not!
If I have time, I would use it to browse to see what I could find. Because of the bunny picture I have posted on my blog, I looked up the topic of rabbits; I found some really cute videoclips including a rabbit who can open envelopes. So browsing can be fun. I would like to use it in my classroom so that I could show clips based on topics that we are discussing. I have no doubt that my students will find all kinds of connections to our English curriculum; in fact, this kind of a websearch is built into one of their assignments. There is another website that I go to periodically and this seems to be an offshoot of YouTube. It is scalled TeacherTube.