discuss is the Area 51 Meta site.
Like all other Meta sites except Meta Stack Overflow, you share reputation between the main site and it's meta, but not badges. You earn badges on Meta sites independently.
The Area 51 software stack is really showing its age here; it is slated to be updated for a while now, but documentation about this kind of detail is indeed lacking.
The new help center for the current software stack has this to say:
Votes on meta do not affect your reputation; your meta reputation is the same as your reputation on main site name (synchronized hourly), though you earn separate badges. You must have 5 reputation to participate on meta.
See the page about meta on Programmers help for example.