Content Types in Sharepoint

1. One Content Type - One Metadata
2. A Document in a Doc Library can be associated to any number of the Content Types we desire.
3. Site Content Types are like Master Page/ Template which will be used in the Site.
4. Once a Doc Lib is associated to the Content Type, The Coulmns in that Content Type will now behave as Local version of that Doc Library.
5. You can Override the Values, Defaults, Req, Optional etc.
6. Limitation is if we want to attach two Content Types to One Doc Library and want the Column to behave differently in either Content Type, we cannot do that Coz it became a Local Version but in both Content Types.
7. If we want the Site Column to behave differently then a Separate Doc Library should be maintained.