How are related apps calculated in android market

Someone can give some information about how related apps 开发者_如何学Care calculated in android market? Why for example X is related to Y but Y isn't related to X?

I've not seen Google publish any details of this, and I wouldn't expect them to as it's commercially sensitive, but I expect the algorithm takes into account some or all of these:

• Apps with similar names
• Apps that comes up together in searches
• Apps that are often viewed in the same session by users
• Apps that have both been bought/installed by the same person
• Apps that are in the same category

The algorithm will share some characteristics with the algorithm Amazon uses to recommend similar products.

I've seen descriptions of apps where the developer simply stated "similar to the following apps: ... " and listed them all.

Now that the length for descriptions has been increased, this would seem like a decent solution to accurately define similar apps.