The interesting thing about the supermarket, is that although there are dozens and dozens of other people in there with you at the same time, your interaction with them is practically zero. You walk by each other, you may occasionally say hello to each other, but that's about it. Imagine how much time, effort and money you could save if you could tap into the collective supermarket wisdom of your fellow shoppers. Think about it.
Some people are produce experts and know how to choose a ripe cantaloupe.
Other people are price fanatics and know which generic products are exactly the same as their name brand counterparts, and which sizes offer the best value. Other people study the cashiers, and have figured out who moves his or her line the fastest and with the fewest mistakes. The point is, there's a lot of knowledge in the heads of all those people, if only you could find a way to capture it. The Saga web site contains an electronic bulletin board section called Trip Talk, in which customers are invited to share information with each other on travel related topics. I make a comment, you write something below it, I come back and respond to your comment, somebody else jumps in, etc.