It's for the on-site Disneyworld DVC resorts. VWL, BCV, BWV, OKW, and SSR.
It's a fee for the night and day transportation from the resorts to the parks is what I've heard. Their transportation at Disneyworld runs pretty much every 20 minutes, approximately 1 hour before park opening and 1 hour after the parks close. Right now as part of their 50 year celebration, the transportation is also free from the airport to the DVC resort for your whole party via Magical Express (no charge). So you wouldn't have to rent a car if you were just doing Disney stuff and not going off property. (Magical Express has to be scheduled ahead of time before arrival at the airport. When Disney sends you your Magical Express vouchers and luggage tags, they also include a free coupon for a Disney pin to be picked up at the resort gift shop).
Disney's Vero and Hilton Head don't have the $95.00 resort fee (they're not at Disneyworld).
One good thing about exchanging into Orlando, if you don't want to pay that $95.00 fee for an exchange into a Disney resort for the Disney parks transportation that runs day and night, there are plenty of other choices in Orlando. We also stay at the Marriotts and Wyndham Palms and enjoy those resorts. If you're doing mainly Seaworld or Universal, then the Marriott vacation club properties are closer anyway.