Here's a review I found about registering online at Target (via epinions):
Where to start!
I was registered with Target.com for my wedding. I had several out of town family members purchase gifts online and have them delivered. The first one I received was the complete incorrect item (wasn't even on my registry). I took it to Target (store) they wouldn't return/exchange it for anything! Then in order to return it to Target.com, I had to pay shipping myself!
The next deliver again, was incorrect. I received 2 of the same gift, instead of one of each gift. Same problem occurred dealing with both Target (store) and Target.com. After numerous phone calls, legal threats, etc. The situation was finally resolved 8 MONTHS LATER! Not to mention a month after our wedding, our registry was removed from the internet making it impossible for "late-gifters" to pull up our registry from their own home.
Since this all happened, I have advised EVERYONE I know from using any of Targets registries, or ordering from them online. Even their in-store return policy has gotten ridiculous. I wanted to make an EVEN EXCHANGE on a Christmas gift (just wanted a different color). They told me that they would have to track that to my driver's license number. I told them absolutely NOT, that's absurd!