Thursday, March 18, 2010

AppBrain launches automatic filtering of "spam" apps


The Android market contains over 30,000 apps. Many of them are very cool additions for your phone, but there's also a fair share of low quality ones. Because it's so easy to launch apps on Android, some developers flood the market with lots of nearly identical apps which have little functionality.

When looking for good apps, these spam apps can really get in the way. I was recently searching for an app to track tennis game results. A number of results I got were by a developer who put 580 applications in the market. These apps are probably just meant to make a quick buck, as they don't have much functionality and all have low ratings. 

On AppBrain these results are now just shown as light grey lines. If you're interested in them, you can still click them to get the full search result.



This improvement makes searching for apps on AppBrain even more enjoyable and lets you find the best apps faster. 

Mathijs for the AppBrain team.

How we did it
We calculated statistics on all developers in the AppBrain database, which covers all apps that are available in the US. In total there were 28,936 apps created by 7,429 developers. Even though the average number of apps per developer was just 3.9, there were 32 developers who launched more than 100 apps in the Android Market. The number of developers grouped by their number of apps launched is shown in the figure below.



We used the ratings given by users to categorize apps as good (rating over 4 stars), average (between 3 and 4 stars), bad (lower than 3 stars) or too few ratings to decide.
The following figure shows apps broken down by quality for each developer output category:



Even though the high-output developers are few in number, they produce a giant proportion of all apps. These apps are often too unpopular to have a rating at all, and if they have, they're less likely to be rated well. However, not all high volume developers are spammers. Two counterexamples are for instance Better Android and K-J Themes. They both have published more than 100 apps, and they're almost all rated quite well.

After some experimentation we let both the fraction of bad apps and the fraction of very unpopular apps determine whether a developer is regarded as spamming the market. The 359 developers that were marked as spammers published over 10,000 apps. There are almost no good apps among those 10K, this means that the overall percentage of very good apps is bumped up from nearly 14% of all apps to well over 20% in our non-filtered set.

Summary
- We analyzed all 28,936 apps created by 7,429 developers.
- 25% of all apps are produced by only 32 app developers (0.4 % of all developers).
- Removing 359 spammers (who in total made over 10,000 apps) boosts the fraction of good apps in the market by 52%.


About AppBrain
AppBrain (http://www.appbrain.com) aims to provide the easiest and fastest way to get and share Android apps. The website is paired with an Android app (AppBrain Market Sync) for easy syncing between website and phone. AppBrain provides personalized app recommendations, fast and relevant search and browsing of other users’ installed apps.
AppBrain is developed by AppTornado GmbH, a leading Android developer team based in Zürich, Switzerland.