User Activity

I sell the same items on ebay all the time and would to set up a Q&A section so that i dont have to answer the same question over and over again. Can anyone advise how I do this and be able to change this when I need to make changes
I am wanting to know if there is a way to advertise with Facebook and Twitter. Eg - after a purchase, the buyer can share with their friends via Facebook and Twitter. Thanks!