A site similar to CareerCup or StackOverflow that is tailored to each user. A short quiz can determine a user's strengths and then an algorithm will direct users to answer questions they are strong in and to view questions they are weak in.
At first it will be targeted towards the programming community. But the idea behind the site can be extended to any community
The idea will be implemented at first through a web app and then later mobile apps. Algorithms to determine a user's strengths and weakness will need to be determined and an interface will need to be designed.
The competitive advantage of this idea is that it will have a clean interface to attract users to the site and users will choose to remain with the site as they see how well it is tailored to them.
Revenue stream would likely be a combination of advertising, sponsored questions and answers, and donations