It took a good few sessions to get the score up.
When you click on the bookworm character all the tiles scramble, apart from the firetiles. The price paid is that a number of extra firetiles are generated plus all the bonus tiles lose their extra value.
Nonetheless, if you think that a firetile is not going to fit into a word by the time it reaches the bottom, a scramble is worthwhile.
I reckon if I'd scrambled the tiles and paid the price before the letter 'U' reached the bottom (you can't scramble when it has reached the bottom) something would have fitted in with it to make a word. So, maybe could have got an even higher score!
...but I think I'll give the game a rest for a while now
Edit: Sara - when 1,000,000 is reached your title is 'Bookworm', followed by Mega Bookworm then Bookworm Supreme. I don't think it changed after that ...not that I noticed anyway.