But I think we need a in-game questing system, where we can see what quests we are currently doing, and what we need to do to complete them.
Otherwise, if we go offline and then come back some days later - we will have no idea of what we were doing.
I suggest something like this:

On that list you can see what your active quests and completed quests are.
If you for example click on Mikhail, then another window will pop up with more information regarding that quest.
// GonzoDark