We registered at Target when we were getting married. We had next to nothing mainly put down practical things like a crock pot, skillet, bath towels, dish towels, etc. We put a few small things like picture frames and such if people wanted only to get something small. Then we did not point out we were registered in the invitations. But if they asked, we told them where we were registered.

I think it's like a lot of things, they can be helpful or they can be "abused" and I've heard some stories of people registering for ridiculous things and almost seeming to make demands of it. At this point in my life, I probably wouldn't register. I have never even liked it when I was asked "what do you want for your birthday?" because I don't like to feel like I'm telling someone what they should get for me.