If you search for 'MacKeeper' on this site you will find hundreds of posts.
This site could use a FAQ (frequently asked questions) section. Some questions come up constantly. e.g.:
- Do I need Anti-Virus software?
- Is MacKeeper a good idea?
- Can I upgrade the processor/video card on my Mac?
- Can I run a version of the Mac OS older than the one it came with?
- How much faster will my Mac be with more RAM?
- How much faster will my Mac be with an SSD?
- Why has my Mac slowed way down recently?
- What's better, a color inkjet printer or a color laser printer?
etc.