Subjects - MSCRM 4.0 takes two steps forward.

Subjects in MSCRM are this interesting tree view structure which allows you to associate cases, kb articles and products in interesting ways. However they have never been customizable, which has limited the usefulness of them, in addition to a few interesting limitations they had. Well MSCRM 4.0 takes two steps forward into making subjects useful, namely:

• You can now delete used subjects. In MSCRM 3.0 once you used a subject it was locked and could never be deleted, even if you updated all your cases etc... to another one. This made management of the tree a nightmare since it basically meant that you got one chance. In MSCRM 4.0, provided nothing is currently associated to the subject, you can delete it. If you try and delete one and it is associated you'll get an error message, simply fire up advanced find and remove/update the linked items and you will be able to delete the subject!
• You can now associate subjects to other entities! But not with the full MSCRM 4.0 power. In fact the only thing is a one to many (1:N) relationship (see attached screen shot), many to one (N:1) and many to many (N:N) are not available. This means that your custom entities or system entities can now use the main subject tree too!

It's still not where it needs to be, namely support for multiple subject trees, customization support (even just adding attributes would help) and better display showing the full structures (ala X > Y > Z) but it is now much more usable than before.