In early 2006 I asked the original author and the current maintainer for their blessing to use the domain "rsync.net" for (re)incorporating the offsite backup component of the ISP I started in 2001[1].
I gave them right of first refusal, etc., and they said my use of "rsync.net" as the name of the company, domain name, etc., was acceptable.
[1] "JohnCompanies"