Another company (see Casual Cafe, Moondo, Flowplay) tries to be successful with browser-based flash games: Fusionfall. Fusionfall is aimed at 9-14 year old kids and features characters from the 3D cartoon network.
To be exact, FusionFall doesn’t use flash for displaying the game, but Unity. For the user it works the same, but he/she has to download the plugin as most games use flash which is most of the time already installed.
Fusionfall launches in Autumn.