They were partners in both business and splitting up certain "areas", that is, countries.
Both Poland as well as the three Baltic countries (Estonia, Latvia, Lithuania) fell under the deal.
Further more, they went through some very big business deals in 1940 and 1941. The Germans had their oil sources not only from Romania, but also huge quantities from the USSR. Ironical it is, but the LW probably used mostly Russian fuel while trying to bomb Britain into submission in the BoB.
The USSR also got their pay, one thing that comes to mind are the blueprints of the Bismarck.
And one fine happy day in the summer of 1941 this was all over....