I am curious if I can create a namespace to save my custom properties. Just like what AEM offers - jcr:title, dc:description, etc . I want to create my own(mysite:customTitle) and use it across my application.
A. is it feasible?
B. If yes, then how to do it? what's the catch and things I must take care of while creating one?
You create a new custom namespace under, the CRX Explorer, http://localhost:4502/crx/explorer/index.jsp, via @berliant's mention. There are no problems when it comes to registering a new namespace. The catch is you need to set up a namespace for each different AEM environment(s); read is fine.