Because most get 1000 followers at least, have 10 of them and have some kind of website selling football related things, tweet your own site will easy get you say 500 hits from one tweet, based on a 1 in 100 purchase or 1 in 100 clicking on an advert which is very low he has made some money from it.
It's a right pain. I have to use it at work to discuss IT troubleshooting with our customers and restricting it to 140 characters is just a ballache. I end up having to split messages into 3 bits to get a point across.
