diff --git a/RelatedProjects.md b/RelatedProjects.md
index 97cdb42..5c32ae8 100644
--- a/RelatedProjects.md
+++ b/RelatedProjects.md
@@ -43,7 +43,8 @@ We are fortunate to have a vast library of high quality Free Software that we ca
 
 These projects have no specific relationship with our project, but they are similar in some ways and so may be of interest.  We sometimes exchange ideas with the developers of some of these projects, especially on the [p2p-hackers mailing list](http://lists.zooko.com/mailman/listinfo/p2p-hackers).
 
- * [bup](https://github.com/apenwarr/bup) is a backup tool with "convergent variable-block deduplication". It re-uses some of git's internals. featured in [//~zooko/TWN9.html Tahoe-LAFS Weekly News issue 9]; licence: GPLv2
+ * [bup](https://github.com/apenwarr/bup) is a backup tool with "convergent variable-length block deduplication". It re-uses some of git's internals. featured in [//~zooko/TWN9.html Tahoe-LAFS Weekly News issue 9]; licence: GPLv2
+ * [backshift](http://stromberg.dnsalias.org/~dstromberg/backshift/) is a backup tool with "convergent variable-length block deduplication", as well as compression and incremental updates. written in Python; licence: GPLv3
  * [HekaFS](http://hekafs.org) is a project to add encryption and other multi-tenancy features to [Gluster filesystem](http://gluster.org). It is sponsored by [RedHat](https://www.redhat.com/), who recently bought Gluster; featured in [//~marlowe/TWN14.html Tahoe-LAFS Weekly News issue 14]; licence: GPLv3
  * [Ugarit](http://www.kitten-technologies.co.uk/project.php?project=ugarit) is a storage system inspired by Venti and implemented in Chicken Scheme. Immature—it currently can't use a remote backend, only a local POSIX filesystem. licence: BSD
  * [GNUnet](http://gnunet.org) is an anonymous, censorship-resistant, file-sharing network. licence: GPLv2+