1) They aren't.. I'm the only person I know who doesnt like Twenty20, and the other is Richard
2) I don't find it interesting in the slightest.. Okay watching a guy trying to slug ball after ball is fun for a bit, and it draws the crowds which is good for cricket.. but give me a day on the grass bank watching a proper game of cricket any day. Cricket is about perseverance, determination, grace and grat rivalries between bat and ball that last for hours.. I love baseball as well, but please don't try and mix the two..
3) I think it is a threat to test match and ODI cricket.. There are only 365 days in the year, and it would be great if Twenty20 can find it's niche.. But money talks, and for those of us that like watching test cricket its a big worry to see the scheduling, and plans for this Twenty20 world championship..
4) I think the only type of fan it brings to cricket games are those that think other formats of the game are boring.. I highly doubt they will support test match cricket, especially if their team aren't succesful.. Time will tell for that one I guess, but in South Africa, test crowds arent increasing at all..
My two cents..