After using Chrome for a decade and switching back to Firefox, one feature I missed was the ability to right-click and Go to [url] directly, for any selected text that vaguely resembles a URL.
I made Goto foo to approximately replicate Chrome's behavior in Firefox, but it would be nice if no extension were necessary.
I don't think .co versus .com is the relevant factor. I can select xample.co by itself, but not as a substring of http://www.example.com. The rules seem so arbitrary and context-dependent that it behaves more like a dice roll than a usable feature.
If a selection to URL feature cares about TLDs, IP addresses, or text beyond the selection range, then it's operating at the wrong abstraction layer. (well, technically Goto foo has a couple lines of code to [bracket] bare IPv6 addresses, but that's not core functionality.)