FrontierVille says 'You can play in a tree house if you give us your email'
FrontierVille wants to stay in touch so much that players who allow the game to email 'em news are now rewarded with a free Tree House. The Tree House originally appeared in stores as a Limited Edition item back in July, and cost 20 Horseshoes. All you've gotta do is click on the "Yes", and the Tree House will be in your inventory and ready to be placed anywhere on your homestead.
Past game offers for ponying up your e-mail included a free horse, and even free meals for your daily energy needs! The latter offer is still currently available at the "Special" and "Energy" sections of the in-game store. Just click on the "Market" icon to get there, then look for "Meal Deal".