Product review (5 stars): Makes in room drying possilbe!
For folks with an indoor dryer, you have little options.  Bottom line is you need to divert both moisture and lint away from your appliance.  I live in a an appartment and have no built in vent.  Be wary of using long pipes to reach a window as the resistance of the pipe length can put serious back pressure on the dryer.  What I recommend is depending on where in your home you place this, make sure that room is well ventilated.  Open a door and window to generate cross draft.  If you are using in or near a bathroom, make sure the vent is turned on there.

As for the lint trap, it's only so-so, I used to put water in it, but I found that there is always a thin film of moisture that seems to pickup the lint so I stopped putting water in it.  Your surrounding environment (climiate, ventilation, etc) may be different, so you will have to play with it.