One for each different browser, which is what the large companies are going to do. If you only want to build one channel, then you are going to have to wait until the dust settles. Perhaps towards the end of the year there will be an industry standard. Or perhaps one company or the other will have demonstrated a substantial market share which helps you decide. You really have to think about what a channel is and what it is for.
Channels are a different marketing model all together.
However, you cannot make a channel from Java. This one I think MS has in the bag. And both are different from push channels. Kai, I do not know why you are creating a channel. I would argue at this time most companies are really spreading their dollars thin in creating channels here and channels there.