Q: Apple ID?

If other people have your Apple ID and password, they can for example download media or apps from Apple, log into your iCloud account and other features from Apple where your Apple ID is the key.

Apple ID is used everywhere in Apple environment. All Apple services uses Apple ID.

http://support.apple.com/kb/HT4895

Duce7 wrote:

Is it dangerous to give out your apple ID ?

Generally, no. However, you should never give out your password, & your password needs to be strong. Apple ID's are some of the most "hacked" ID's in the world, for obvious reasons.