I use them pretty liberally, actually because I hate bright lights indoors. I have strings of the icicle style lights hanging from the ceiling of my living room along both the east and west walls. Having one or both lit creates a nice, diffuse lighting scheme, especially because the ceiling is quite high (~12 ft) and the room is sizeable. I also have a small string behind my TV table and on top of the bookshelves, both of which are a sort of medium-colored wood. Those strings are not seen at all; they just create a sort of glow around the furniture.
My friend's backyard, the only actual yard anyone I know has, ergo the sight of all Summer parties and BBQs etc, is essentially a narrow, gated bricked alley bewteen his building and the next, with some trees and planting boxes etc. We have hung a canopy of the net lights, which is just great at night, does not attract bugs like a porchlight would and is, again, nicely diffuse. We'll probably wrap the big tree by the grill this year as well for better lighting back there.
Just to clarify, none of the aforementioned lights flash, and they are all white lights. No one is going for the arcade look here.