Sourcegraph CEO here! Thanks for mentioning our Chrome extension. It adds IDE-like code intelligence to GitHub.com and other code hosts (when viewing code files and diffs/pull requests): hovers, go-to-definition, and find-references.
The extension is awesome, it could just have a bit more polish in the firefox version (font and icon don't seem to load properly in the browser bar, at least in most recent version of the firefox dev edition). Thanks for your hard work on sourcegraph though!
Thanks for the feedback! I'm glad it's helping you out in your day to day.
We're currently working on bringing the extension to Safari. This makes the extension more aware of browser differences which will allow us to keep everything polished in all of the browsers we support.
Keep your eye out for updates and as @sqs said, we'd love to hear any feedback you come across @srcgraph!
Check it out at https://chrome.google.com/webstore/detail/sourcegraph-for-gi.... Send feedback our way @srcgraph!