How will Airbnb create its additional services

Not all hosts seem to have this, but I have as an option on the AIrbnb site, on the message thread with any accepted guest, "charge for a paid amenity"  which shows up in the top box on the message thread.  You can click on either "reply to ___ " or "charge for a paid amenity" .  This is where I can charge the guest for some service, like a horseriding lesson (I don't have a horse, but if I did) or a kayak trip (no kayak and no river, but some hosts have that) or ride from airport, or bike rental etc.  I am not sure if Airbnb charges a service fee on any amount you bill the guest that way, but if you don't have the option for that charge then the point is moot.  


For bike rentals if you want liability insurance and coverage in case bike is lost or damaged or stolen, you may want to list your bike on "the Airbnb for bikes, " eg, and then your guest can just rent your bike on that site.  Or you can have them pay you directly for the rental plus a cash security deposit in case of loss/damage.