Now the question is what incentive could we give the users who are sharing their own skills?
First answer would be to send them traffic in analogy to what happen in web search. Anyway, I am not sure that this would be valuable for my friend Giuseppe who claimed that he is an expert in Photography. Why sending traffic to his Facebook page should have any additional value to him?
The second answer is to share revenue between my skilled friend Giuseppe and Facebook whenever Facebook shows Giuseppe among the friends skilled in Photography. The more likes Giuseppe gets the higher would be the chances to be retrieved for a search about Photography. Whenever ads shown for that topic are clicked Giuseppe will get a little amount of the revenues generated. He produced the content, he has the skill so he takes some direct money for it. In my view, this model would give a natural incentive to share skills and to get likes for those skills.
The third answer is still to about sharing revenues, but would be based on inserting ads into skilled pages. What is a skilled page? pretty simple. If Giuseppe declares a skill in Photography he can create a special page on his profile very similar to the traditional timeline but focused just on Photography. All the ads shown in that page are about the Photograpy topic and again there should be some form of revenue sharing as form of incentive to produce high quality, curated skilled pages. After all, Giuseppe is the expert so he has to tell something about his expertise.