Nintendo Channel
If Wii Channels are supposed to represent the different channels on a television, then the Nintendo Channel is the one with all the commercials on it. But you only watch the commercials you want to watch. Isn't this how all advertising should work?
The Nintendo Channel exists to get you to buy games. Hell, you can even help other people buy games! But I'm getting ahead of myself. The channel achieves its goals through a number of means.
The first is videos. The channel is primarily a list of streamable flash videos, which includes game trailers, game footage, game interviews, game explanations, et cetera. It's only a little more fleshed out (in terms of Nintendo products) than what you might find on an online game video website, but the channel doesn't bog you down with additional ads, prologue commercials, or any of that other crap. Simply put, this is the best source for Wii and DS game videos.
Another way the channel facilitates you buying more games is through lists of games, categorized by title, platform, genre, release date, and so on. You can see what's coming out soon, recently released games, or back catalogues in a genre you like, for instance. And since it appears to just be using the same database as the Nintendo website's game list (since the Nintendo Channel itself is on it), a lot of games have even more videos that you can watch here for an idea of what the title has in store. And every game page has a link to take you to an Internet Channel page where you can buy the game online. Now not only do you never have to leave your house, you never have to leave your Wii!
An extension of this is the channel's recommendation system. I haven't delved too deeply into it yet, but based on some survey-style questions, you can use the Nintendo Channel to recommend for or against games you've played, based on demographic and interest categories. The clever part of this feature - that is, what makes it better than the Glog - is that it checks your Wii play history, so you can only recommend games you've played for at least an hour (thus keeping out almost all user-input garbage).
Finally, and this is actually the biggest reason you should download the channel, it is an excellent sales vector for DS games through the DS download station feature. Yeah, just like a real DS download station! Pick an item from the list of available demos and things in the channel, and your DS can download it right from your Wii, through the magic of The Internet. I just used it to play demos of Crosswords DS and Ninja Gaiden: Dragon Sword. Awesome.
This is the kind of channel that really reassures you about your purchase of a Wii. I even want to get Emergency Heroes now. What miracles this machine is capable of!
Progress: Gave Up -- Perused