Radio Frequency Identification (RFID) works a lot like barcodes letting you scan products, or anything else you put a barcode on, and instantly get serial and product information on that object. The big difference is that barcode scanners physically need line-of-sight to the barcode while RFID can automatically read a tag if it is within range.
Check out my post on RFID vs Barcodes for more information on how these technologies compare.