What makes StackOverflow so useful are tags. Tags are the single most important feature. Here is a snippet of what you see when you search tags for Delphi:
|StackOverflow Tag Search - Delphi|
By following this link you get a list of which users have answered the most questions and which users have asked the most questions relating to this tag. By drilling down onto the users profile, you can see all the answers and questions this user has participated in.
You can very quickly build a list of your favorite StackOverflow Delphi users. Reading answers by these users will most definitely increase your knowledge about Delphi.
Delphi Tags Top Users
FireMonkey Tags Top Users