Thorsten, you're a bit late to this party. They announced it months ago, and implemented it in February. Expedia paid $3.9 Billion for HomeAway, and they want to make their money back. For months, Brian Sharples, the HA CEO had been complaining that their "take rate" was too low, relative to AirBNB and other sites.

Not only have they implemented the booking fee, which they receive when the booking is made, they have added something called "Best Match". It is even more insidious. They arrange the sort order according to an algorithm which lists properties according to the searcher's greatest likelihood of booking, what they called "conversion rate". Properties that are already booked for the dates specified drop off the search results. So even if a guest's dates might be flexible, they won't see your property. If a searcher doesn't give dates, they look to see where he is located, assume he will behave like other people in his area, and show him places available during dates searched by others in his geographical location. Pretty scary, really.

Other sites do not receive paid subscriptions, which, with VRBO and other HA sites, range from $400 to over $1500 for platinum listings with regional bundles. Folks paid big bucks and are not getting any inquiries or bookings, or far less than they got before. As you say, the terms were changed during the course of the contract and without notice. So there are now some class action lawsuits.

Upon renewal, it looks like everyone will be forced into the new system, like it or not.

Do not be tempted to put something in your copy about "contact us directly to avoid the fee", because they are using automated searches to find those listings and block them. The best defense is to upgrade your personal web site and use the unique name of your property in the heading of your listing. That way, if someone finds "Gorda Cove" or whatever, they can Google that name and find your personal web site. Another defense when your listing expires is to switch to PPB, which will keep retain your listing and reviews.

This is just a synopsis of the situation. Lots more details are available at
https://community.homeaway.com/community/us.