I've read a LITTLE bit about some of the RFID possibilities. If you've ever gone on the ET ride at Universal, there's a parallel there. Before you board ET they ask for your first name. Riders names are entered into a computer and during the attraction ET speaks the names of folks riding past at that moment.
My understanding is that an RFID chip could be embedded in theme park tickets or room keys and be integrated in attractions throughout WDW. Audioanimatronic characters could "speak" your name while riding through a dark ride. In various ways, attractions could be programmed to customize the experience based upon guests favorite Disney character, favorite color or parks/attractions visited earlier in the trip. The CMs operating attractions like Turtle Talk and Monster's Inc Laugh Floor could have access to guest names, hometowns and other info about their audiences. It would be part of the new virtual queuing system being tested at parks where guests claim a spot in line and can then wander around a designated area waiting for their group to be called rather than walking between bars for 20 or 30 minutes.
Really the sky is the limit. It all depends on what extent Disney wants to integrate the technology.
There are really 2 benefits for Disney to implement the use of RFIDs. One benefit is what the guest gets from it (enhanced features on rides, queue systems, dining, etc as mentioned in the quoted post above).
The other benefit to Disney would be mostly unseen by the guest. They would be able to micromanage things down to the smallest detail. Currently, they know when you enter a park, but not when you leave. They roughly know how many guests ride each ride, but not who, etc. With RFIDs, they'd have a wealth of information and statistics. Yes, they'd know exactly what you are doing in the park, and what everyone else is doing. That could then be used later for marketing purposes. Advertisements on your room TV would be customized as would future emails. Maybe they noticed which restaurants you walked into, and would show an ad on your TV for a restaurant that they think you'd like. Or maybe they know that you rode the Pirates of the Caribbean many times and send you an email later with an offer on POTC merchandise. The data may show that during your stay at the Wilderness Lodge, you stopped by the Polynesian several times. Then when you get future emails about visiting WDW again, it would suggest staying at the Polynesian. They'd know everything about your movements - how many times you ride a ride, when, which ones you don't ride, which restaurants and shops you walked into, how long you stayed in a park, which form of transportation you passed through, etc. Yes, Big Brother would be watching, more so than now.
They would also have a ton of statistics and could use it to more efficiently operate the parks. Perhaps they notice that guests from on-property resorts eat at certain restaurants or ride certain rides/attractions more than off-site guests. They could use that to decide which things to have open during EMH. They would have real-time data on rides: more or less cast members could be positioned at a ride based on real-time usage. The wait time listed on the standby line would be an exact number of minutes listed, as they'd know exactly how long it's taking every guest to make it through the line. (They do have a system in place already, but RFID would be continuous and more precise). Perhaps the RFID data shows that people in a particular Main Street gift shop tend to spend more time in front of a certain merchandise display. They can use that data to decide where to place that merchandise in the store to maximize sales. These are but a few examples, some more likely to occur than others.
The possibilities are endless, both for the guest experience, and for Disney in terms of marketing and park management.
What are the "seven parks"?
When your money is gone they will send you spam emails to your cellphone about the newest promotion at Disney Visa! 
