Here's an evernote file of things I've found and liked around the internet re: 2 sided marketplaces. All digital, although not sure exactly how "successful" they are - but more for reference.

Quality / Copywriting
https://www.yourmechanic.com/works#mechanics
https://www.airbnb.ca/?locale=en
http://powhow.com/

Community Engagement
http://www.houzz.com/ideabooks
https://www.healthtap.com/
https://www.airbnb.ca/wishlists/popular
https://www.wello.com/class/set/Yoga/

Categories / Search
http://www.etsy.com/
http://fiverr.com/
https://www.airbnb.ca/s/moncton?source=hdr
http://takelessons.com/search?q=4gq30T

Deliver of Service
www.hotelstonight.com
www.uber.com
https://www.medicast.co/
www.wello.com
www.takelessons.com
www.taskrabbit.com

How it works
https://www.taskrabbit.com/how-it-works

https://www.zaarly.com/howzaarlyworks
http://takelessons.com/students/how-it-works
https://www.wello.com/how-it-works/
https://www.medicast.co/how-it-works
https://www.healthtap.com/#how_it_works
https://www.wello.com/how-it-works/
https://www.odesk.com/info/howitworks/client/
http://www.guru.com/emp/takeTour.aspx

The Why
http://nest.com/smoke-co-alarm/why-we-made-it/#nobody-ever-looks-up

Supply Side
https://www.elance.com/q/find-work

http://www.guru.com/pro/index.aspx

https://www.odesk.com/info/howitworks/contractor/

http://takelessons.com/teachers

https://www.zaarly.com/selling
http://www.skillshare.com/teach
https://www.udemy.com/teach/
www.powhow.com/open-your-own-studio
https://www.airbnb.ca/rooms/new

Conversions
http://www.justanswer.com/
http://www.skillshare.com/

Referals
http://www.powhow.com/open-your-own-studio
uber.com/invite/rjif2

Subscriptions
http://www.powhow.com/open-your-own-studio
http://premium.docstoc.com/subscribe/plans
http://www.rocketlawyer.com/plans-pricing.rl

Help Center
http://help.zaarly.com/
https://www.airbnb.ca/help

Pricing
http://www.rocketlawyer.com/plans-pricing.rl
http://www.powhow.com/open-your-own-studio
http://premium.docstoc.com/
http://mixergy.com/premium/
http://wistia.com/pricing
https://teamtreehouse.com/subscribe/plans