Honestly I'm not trying to sound negative--but the whole movie is about failure. If you are more interested in starting a business one day this can save you many headaches. Business is hard but there is no reason you can't succeed as long as you have a GOOD idea, the money to pursue it and the will to see it come to a creation. Most people during the dot com lacked solid ideas that common sense tells you would do well.
In this documentary it doesn't explicitly comment on the waste and stupidity but a smart individual can see it. The millions they blow through (literally like what, 50 million?) the lack of actual product and idea, the overstaffing and stuff you DONT NEED to begin with.
Now that I think about it you should definitely buy it if you are interested in starting a business. If you are just into computers/internet then no, you'd dislike it greatly.