What is a Release defined as?

Just wondering since there doesn't seem to be a hard definition any where on the site (at least that I have come across); what is considered a release? 
Can we add Limitied/Collectors Editions, Steam Releases, Game of the Year Releases? 

 I think you can add all of those, there have been many threads asking for limited/collectors editions to be released.
 
Edit:  They deleted the collector/limited editions that had pages of their own, not that had been added to releases.  Sorry that was unclear.

" Can we add Limitied/Collectors Editions, Steam Releases, Game of the Year Releases?  "

Essentially we have one release per region for the standard game, and anything that has something different (e.g. GOTY editions, collectors editions) can have their own releases. Assuming the steam release is the same as the retail release (minus the box & manual, obviously), there shouldn't be a need to give it a release in our database.

Sometimes a game is released digitally first, and then a retail version comes later. In those cases I think it makes sense to have separate digital and retail releases. Just as long as you don't create a separate release for every digital distribution service it's available on.

I was thinking about this today in relation to releases on Good Old Games. While technically the game you're getting is usually similar to the original PC release, it's had a lot of work done on it for compatibility, and they tend to add "goodies" to each release like artwork, soundtracks, etc. Should releases like this be considered separate?