On installation of Acrobat Reader, Adobe apparently installed other things without indicating so, not telling you what they are used for, etc. - very annoying. Acrobat.com, AIR, etc. I removed them, after finding out that they are more or less advertisements.
Also, they created several constantly running processes, even though the Reader is not running, and I would like to know what they are use for, and if I need them:
1. PDF Shell Extension
2. Adobe PDF Link Helper
3. Uninstall Adobe Download Manager
4. Adobe ARM
5. Adobe Reader Speed Launcher
I wouldn't mind any or all of these running, when Reader is running, but they are constantly running and chewing up memory and probably processor time.
Foxit appears to be much cleaner - no processors or bloat ware.