Many corporations do not allow their brands to be used in domain names. This is to prevent negative representation of their company and such as phishing. Some of such companies companies include:
1. 3M
2. AOL
3. Apple
4. Ebay
5. Facebook
6. Google
7. Habbo
8. Hotmail
9. Microsoft
10. Ralph Lauren
11. Runescape
12. Ugg
13. Walmart
14. Yahoo
In choosing a domain name, avoid the brands of trademarked companies. This will ensure that you are not imitating or infringing on a public entity.