D'Snowth said:
I never had to download anything to watch the videos on YouTube.
Your computer probably already had an up-to-date Flash Player and Java installed. But if that isn't the case, then someone must've done it while you weren't around; you need those two things to watch YouTube stuff.
As for the topic maker's question, I can't find a good answer for it--or at least, I can't find a good way to describe all the technobabble involved--but pretty much every site with videos requires some program or another for you to watch it. Sorry for not providing the best answer, but I guess the "required installations" stuff is just a way of life with computers.
~ Morgan "Can't Do Techno" Goat
PS: Usually libraries, whether at school or in the community, have PC's that are up-to-date with the basics, which I guess is a good thing, but in your case, it might be bad, depending on how far you live from it. It might only be worse if the filters are strict (ie: doesn't allow you to look through sites with the subject of or any involvement with video/computer games, MP3s, "stupid stuff", etc.).