show the position of an app in its category.
You should add a graph to the changelog that displays at what position your app appears in the market categories you chose over time.
This would be very interesting to see as a graph.
We will think about how to implement this.
One difficulty is that the available apps are different on each phone. (based on the country, android version, provider, screen resolution etc)
This means that an app has many different positions in the category, depending on what phone you use to look at the market.
Very good idea. Because an application I have may be surpassed by another one. I would like to know/track that.
For example: in the list of installed apps have a "ranking" and/or a list of other apps that does the same thing or are similar.
This is a great idea. I think just use the Nexus One as a baseline for this sort of thing. It's Google's "official" phone and will have the biggest and widest support.