<i>&gt;A central-hub choice of implementation shouldn&#x27;t be confused with a centralization requirement however.<p>&gt;Indeed, we had this, in the form of NNTP and older news servers;</i><p>You&#x27;re focusing on the <i>technical</i> aspects.  The other forces are <i>social</i> and <i>economics</i>.  Both of those lead to centralization.<p>Take your example of Usenet news groups.  Yes, in a technical sense, it&#x27;s decentralized but once you get economics&#x2F;money involved, what happens?  My ISP like Verizon doesn&#x27;t carry all newsgroups (e.g. exclude newsgroups with large binaries.)   Or another ISP may carry more newsgroups but the retention is 1 month instead of 1 year.<p>So the economics converges to an central entity like Deja News that emphasizes the archival of usenet posts.  Then Google buys them (Google Groups).  Google Groups is now &quot;centralized&quot; for finding very old usenet posts.  Conceivably, any of us besides DejaNews could have archived the posts but <i>we didn&#x27;t spend the money on harddrives to store it</i> whereas DejaNews <i>did</i>. Hence, we end up with a centralized archive.<p>When I had Verizon, their newsgroups feed was very poor.  I therefore paid $10 extra to GigaNews because they had everything with multi-year retention.  That&#x27;s another &quot;centralized&quot; hub driven by economics.<p>Looking only at the usenet RFC technical specs for distributing news posts doesn&#x27;t reveal how the economics makes centralization emerge.<p>As for github&#x27;s centralization...<p>A lot of us want to host a public git repository.  Hmmmm... if github didn&#x27;t exist, what do we do?  Pay for a VPS for $9&#x2F;month plan and host git on that?  What about extra bandwidth costs if it&#x27;s a popular repo and lots of people are cloning it?  That&#x27;s a lot of ugly financial bookkeeping that we don&#x27;t want to do since we&#x27;d rather just concentrate on programming.  Wait -- there&#x27;s an <i>ABC company</i> out there that lets me conveniently host a git repo there?  For free?   Sign me up!<p>That &quot;ABC company&quot; by way of economics and social dynamics has turned out to be Github and BitBucket. And since Github has been winning the mindshare, you get centralization.  There is no irony in git-the-tool being distributed and github-the-focal-point being centralized.