Knowing the ranking of an app. on market
There are ways to check your app. market ranking. The easiest way is to check it online by going to the website listed below. Click this website and it'll direct you to the correct site to check your app. ranking.
The link located above is the tool to let you search the app. ranking on a different sections of the Android market applications. Google website has way to calculate market rankings by languages. It limits from 800 top apps in rows in all, real time.
It may interest you to check how the ranking vary on different languages and continent. You can also check the app market ranking by doing the following steps below.
id=apps_topselling_free (free app)
cat=TOOLS (tools section)
start=24&num-24 (will display 24 most popular)
hl=it (listed in Italian)
If you adjust the field and through lots of pages, you can do different things. Things like Open Signal Maps is 768th among all free apps provided by Android market in English language.
Knowing the ranking of an app. on market
Hi Aaralyn,
   All the applications had their own level of marketing in accordance with the developers. For the Android Market they rank their applications in four levels such as: Every One, Low Maturity, Medium Maturity and High Maturity. To classify those level they also created their own guidelines to rank apps.  Must Check the apps' contents, the generated content done by users, products apps, and how they advertise those apps.
  Here are the sample contents that Android Apps not permitted:
- drugs and alcohol, real form of gambling, using bad speech or language, use of awkward humor, sexuality content, Â and real form of violence
   Hope this might help you.
Thanks.