I have recently created ProofSwap because I was really struggling to get social proof for the app that I have built prior to this one.
I am an introvert and I have a hard time cold DM'ing people asking for favors (even I always offered to return the favor, of course). It just doesn't feel right to me.
Therefore, I thought, why not creating an app that handles that initial connection automatically based on mutual interest.
You can just log in with X and create a listing - then you can choose what you want (Tweet, Backlink, Testimonial, Feedback, Other) and what you are able to give in exchange (same options).
After that your project is listed and can be viewed by other users - they can then post a Tweet for instance and share the link with you, you can then accept it or file for dispute if something is wrong or needs a review.
Then, of course, it's up to you to return the favor. I have implemented a merit system that allows you to earn credits, and I am in the process to implement a exchange rating system (basically star-ratings for users).
Users with a lot of credits and a good rating automatically get listed further up top and maybe eventually highlighted later on, so it will be easier to get exchanges.
There are still a lot of moving parts, but I really love how this is developing. If you want to check it out - it's completely free to use. I was planning to finance it entirely via Sponsor Ad Slots in the Sidebars (like Marc Lou's TrustMRR in the beginning).
It would be awesome if you check it out, or if you have some feedback / feature requests, I'm all ears!
Happy shipping!