User Agent String:

Mozilla/5.0 (iPad; U; CPU iPhone OS 3_2 like Mac OS X; en-us) AppleWebKit/531.21.10 (KHTML, like Gecko) Version/4.0.4 Mobile/7B314 Safari/531.21.10gin_lib.cc

The breakdown

Explanation of what each part of the User Agent string represents.
Part	Type	Description	Version
Mozilla/5.0	Misinformation.
iPad
U	Encryption	Supports 128-bit or better encryption
CPU iPhone OS 3_2	Operating System	iPhone OS, ARM CPU	3.2
like Mac OS X	Misinformation.
en-us	Language	English (United States)
AppleWebKit/531.21.10	Rendering Engine	WebKit Rendering Engine	531.21.10
KHTML, like Gecko	Misinformation.	Apple WebKit is based on KDE KHTML
Version/4.0.4	Web Browser	Accurate Browser Version	4.0.4
Mobile/7B314	Build	iPhone Firmware Build	7B314
Safari/531.21.10gin_lib.cc	Web Browser	Apple Safari	531.21.10gin.lib.cc

What is a "User Agent"?

A User Agent is a short string that web browsers and other applications send to identify themselves to web servers.

Unfortunately, most browsers falsify part of their User-Agent header in an attempt to be compatible with more web servers.

Tips

Click on your user-agent string (in the green box) to get a link that you can share with other people.
Visit whatsmyua.com/ua/[any-user-agent-string], the site will give you a breakdown for that string.