Access management
Tracking of goods
Tracking of persons and animals
Toll collection and contactless payment
Machine readable travel documents
Smartdust (for massively distributed sensor networks)
Tracking sports memorabilia to verify authenticity
Airport baggage tracking logistics
I never knew it had so many applications, but I have been familiar with these chips for many years...
I have loved dogs since I was very young, and learned about the pet tracking option with RFID tags. I used to think it was a snobbish idea, but now that I've adopted a rather run-crazy wolf-like dog that has one - though we've never needed it - I'm absolutely open to the idea. Every animal is checked for one of these chips when found by the pound. The computer system can then tell the employees all of the owner's information as well as information on the animal. This was an enormous comfort when first acclimating my dog to life with us in Utah.
This is also something that could be useful in commercial enterprises. Amazon uses something similar, and we are all familiar with the less sophisticated barcode. These chips, however, can be read from anywhere within up to 3 meters, whether or not they are visible. This would allow industries (I'd like to include the E-Commerce department of the BYU Bookstore where I work) to find and track items for customers without the nuisance of searching tags and matching barcodes.
Now, RFID chips do raise questions on personal security and privacy. If we can track animals and merchandise, why can't we track people? I know there are plenty of sci-fi stories in which the people have chips embedded in their skin so "Big Brother" can track them. It is certainly something to fear, but what if we could use those chips in emergency situations so doctors know exactly what healthcare to give? We could have easier and faster identification for police to use etc. Again, do we want that kind of overseeing, or do we retain independence? It's a question for the ages.