CanBug4AnyCode

First a question: Do you also think to categorize/tag the posts (give user the opportunity to choose the tags) (eg: the Q&A section in linkedin)?

Use case: If there are categories, you can (optionally) show user's strengths in the profile page. (eg: user has posts under "DIY stuff", "cooking", "gadgets", "coding" ....)

With that profile, I also would like to see the average thank-rate of the user, and see his other most thanked posts that might interest me.

Ranking: I'm not sure about the ranking, but you may consider to provide also "top" lists for the categories, so I can also the most appreciated posts of a domain/category of my interest

Finally: If there would be a way to see the "top" lists, there also should be a way to prevent abuses by bots/automation etc

There are many other ideas that might be linked to yours, it's worth to give it a try :)

"Karma" sounds a good point to promote:)