"Another new spreadsheets feature are revisions"
This would probably read better as:
Another new Spreadsheets feature is "revisions"

Spreadsheets is singular and is a proper title. The feature ("revisions") is also singular. "Are" shouldn't be used at all.

Sorry to be a grammar nazi. Not trying to be holier-than-thou, but it took me a while before I could get the sentance to make sense to me.

Thanks Dinah, corrected! Corrections are always welcome.