Flickr Fun? Not!

I am questioning the wisdom of my decision to learn Web 2.0. Dutifully, I have started my blog. Dutifully, I have tried to explore and have fun with Flickr. I have even set up a free account on Flickr and done some "exploring" . I don't have any idea of what they are talking about most of the time. I do not know the jargon and don't know what they refer to. I have no photos to upload. I haven't been able to discover from what I have read whether I can upload interesting stuff (images, photos, etc) from Internet or not, nor have I been able to find any instructions for doing so. A "mashup", Hunh??? I really am lost and confused and that is NOT fun!