Let me ask you about a particular case then :). I am in a group that develops a natural language parser for Dutch. It's open source, but so far we have been hosting it in a private Subversion repository on our university servers. We do provide a read-only (somewhat hidden) git mirror of the tree, but we have considered publishing it as an public git repository, but were always worried that the repository is too large for hosting it externally.

The git repository has existed for one and a half year, and the bare repo is currently 1098 MB in size*. Would hosting such a repository on Bitbucket be considered fair-use?