Economics of BitTorrent communities

Abstract

Over the years, private file-sharing communities built on the BitTorrent protocol have developed their own policies and mechanisms for motivating members to share content and contribute resources. By requiring members to maintain a minimum ratio between uploads and downloads, private communities effectively establish credit systems, and with them full-fledged economies. We report on a half-year-long measurement study of DIME -a community for sharing live concert recordings -that sheds light on the economic forces affecting users in such communities. A key observation is that while the download of files is priced only according to the size of the file, the rate of return for seeding new files is significantly greater than for seeding old files. We find via a natural experiment that users react to such differences in resale value by preferentially consuming older files during a 'free leech' period. We consider implications of these finding on a user's ability to earn credits and meet ratio enforcements, focusing in particular on the relationship between visitation frequency and wealth and on low bandwidth users. We then share details from an interview with DIME moderators, which highlights the goals of the community based on which we make suggestions for possible improvement.

Systemic Risk and User-Level Performance in Private P2P Communities

“…However, many measurement studies [5], [12] show that the popularity of a file decreases quickly after it is first published. In this section, we analyze the effects of SRE and evaluate our proposed strategies under dynamic file popularity.…”

“…However, they did not propose strategies to solve the problem. Kash et al [12] demonstrate that in a private community named DIME, after a period of freeleech, there are more download activities in the community. This is consistent with our theoretical result that during a pre-crunch state, injecting credit will increase the system throughput.…”

On the sustainability of credit-based P2P communities

“…Increase in download activity as the aftermath of freeleech period has been demonstrated in [14]. The study is based on real-world measurement of the DIME private BitTorrent community.…”

“…Although we use the terminology 'initial amount', the different scenarios we study here resemble actual situations in real-life BitTorrent communities after so-called freeleech period [14]. During these periods peers do not need to spend credit for download.…”

Empirical investigation of BitTorrent community graphs

“…On the other hand, in open BitTorrent communities (represented by the Synthetic graphs), where no explicit rules are (and could be) applied regarding the seeding, it is better if each seeder uploads in one swarm only. According to Kash et al [25], observation of a private BitTorrent community revealed that many peers are seeding in multiple torrents. While it is practically impossible to find relevant measurements regarding the open BitTorrent, Cuevas et al [26] shows that, on average, a regular publisher (user who injects new content into the BitTorrent network) seeds concurrently only in one torrent.…”