Well, just about anything that involves scapula retracion or shoulder elevation requires the traps. In shoulder elevation, the traps works along with the deltoids to cause the motion. Case in point, the simple movement of the clean and press requires shoulder elevation and a shrug movement, then shoulder elevation and a pressing movement. Hits the shoulders and traps quite hard, not to mention the triceps. Seeing as the upright row is just a half a version of a power clean, well, yes, it works both the traps and delts. The only thing I will say about the upright ow in the way of caution, is that a narrow grip is hard on my wrists, and doesn't seem to transfer well to my basic pulling well, however, with a grip thats about shoulder width or wider, no problems, I love them.
Now, your basic rowing movements hit the lower and mid traps quite hard. If you are doing those, I see no reason to try to target it, however, I have seen some PL types lie face towards the board on a 45-60 degree incline bench, and o shrugs in that position. Personally, I think it's over kill.
Hope this gives you some ideas.