For the last 5 years I have developed about 50+ Facebook page tab and canvas application with gaining extensive knowledge on Facebook APIs. I have made facebook campaigns which includes photo contest, quiz contest, canvas games etc. In those apps I have used default and extended permissions from Facebook for apps. I have also implemented invite, share and custom voting feature to make it vital gaining massive impact on the brand or business I was working for. If you want something similar or just want to know what can be done feel free to contact me.