What does Other mean on my iPhone memory?

I have an iPhone 4s 16GB. And about 5.20GB of memory is taken by 'Other' (yellow bar) on my phone.

What does that consist of and how can I reduce my memory for it to save memory on my phone?

Corrupted data, Texts, call history, and many more

To fix, delete all unnecessary data.

If you are still full:
http://support.apple.com/.../kb/TS1503