GitHub is pretty OK as a file browser for livegrep search results to link to, but it has a few limitations:

• It's a little slow -- I think of it as quite slow, based on some trials just now it's not bad so maybe it's improved, but it's still not as snappy as livegrep itself;
• Because it's not livegrep, we can't add UI for exploring the codebase with further livegrep searches, cross-references, etc.;
• Some of us have a different, slower backend -- e.g. at Dropbox we use Phabricator, which I think is a decidedly better code-review tool but the code browsing is not as fast as GitHub let alone livegrep.

This used to be a frequent feature request on our internal instance at Dropbox, and then @christoffer built it :). @jboning plans to send a rebased version of that implementation upstream here soon.