This is not your standard chart based on app numbers per categories. This chart is based on data from 342.000 Apps isntalled on over 100.000 Devices recorded from April-October 2014. This gives a better overview on what on how popular a category is with smartphone users - not just how popular it is with developers. If you go by lists from Appbrain or App Annie you might think that Business, Photography and Social are hot categories ... but they are not or even worse, they have plenty of downloads, but only from  a few apps. Trying to push an app in these categories might be very difficult. I did not lump Games into one value here to give the full picture - but all game categories combined is about 50% larger then Tools, the single most popular app category. And here is the list:

1. TOOLS
2. PERSONALIZATION
3. EDUCATION
4. ENTERTAINMENT
5. LIFESTYLE
6. BOOKS AND REFERENCE
7. TRAVEL AND LOCAL
8. GAME,PUZZLE
9. NEWS AND MAGAZINES
10. MUSIC AND AUDIO
11. PRODUCTIVITY
12. GAME,CASUAL
13. BUSINESS
14. GAME,ARCADE
15. FINANCE
16. APPLICATION,SPORTS
17. COMMUNICATION
18. HEALTH AND FITNESS
19. SOCIAL
20. TRANSPORTATION
21. SHOPPING
22. MEDIA AND VIDEO
23. PHOTOGRAPHY
24. MEDICAL
25. GAME,ACTION
26. GAME,CARD
27. GAME,RACING
28. GAME,SPORTS
29. APPLICATION,WEATHER
30. GAME,EDUCATIONAL
31. GAME,SIMULATION
32. GAME,FAMILY
33. GAME,ADVENTURE
34. GAME,STRATEGY
35. LIBRARIES AND DEMO
36. GAME,TRIVIA
37. GAME,CASINO
38. GAME,ROLE PLAYING
39. GAME,BOARD
40. GAME,WORD
41. COMICS
42. GAME,MUSIC