The Diablo 2 Wiki archive is available for anyone looking for information on Diablo 2. All information here is pre-D2R but contains a lot of useful information that is still relevant. Updated sections for new D2R features can be found on the PureDiablo Diablo 2 section
From Diablo 2 Wiki
All information on the Diablo 3 Inventory can be found over in the Diablo 3 Wiki page for the inventory.