Following a recent NYC "mobile camp" (good coverage from Mobilitee), Scott Shaffer commented the following in his excellent Blog:
"A couple issues I still see with PWC.
What or where this QR code give me? Outside of Semapedia ("Internet Dictionary") there is no mainstream application that encourages people to click on a code. Price comparison is the most discussed PWC application but that is for 1d codes (barcodes).
One of the reasons I like the proprietary code players Nextcode and BeeTagg is because their codes are distinguishable AND you know what information you will get when their codes are scanned.
There has to be a reason, or an expected outcome, to get people to scan a code. Curiosity won't drive adoption."
You can read the complete post here.