"Since 2007 we have been deploying and improving our Bandwidth-as-a-Currency vision. We are fans of Bitcoin, but also showed in an early analysis the flaws in this concept. Bitcoin differs from our work, but also has many similarities (our work pre-dates Bitcoin).
The foundation of our approach is making repeated successful interactions between actors explicit and durable. Cryptographically signed records of successful encounters serve as proof-of-work certificates. The validity and value of these certificates is determined by our reputation system, explained above. Our Bartercast protocol is designed to distribute proof-of-work certificates. It was first deployed in 2007 and improved over the years, for instance, it can now be used to give priority to cooperators. Relaying for anonymity and seeding in Tribler constitutes work which is rewarded with a signed certificate. Our current implementation has been tested extensively on our server-cluster and should be ready for deployment within Tribler soon. Our long-term focus is ensuring perpetual scalable of proof-of-work systems.
The credit mining part of our proof-of-work system is ready in Beta form. See the above screenshot from November 2013 showing the boosting of various swarms. Note the investment yields of "struck gold" and "poor" in the right column."
Source:
https://github.com/Tribler/tribler/wiki
