I recently downloaded a free iPhone app called StickyBits that lets you scan any barcode and attach comments, photos, video, audio or links for others to see when they scan the same barcode.

StickyBits and services like it have amazing potential to change how we decide what to buy. Imagine scanning any barcode and reading quick reviews or seeing photos or videos of the item in use.

But here’s the problem: these apps and sites only as helpful as the people using them.

I recently read Socialnomics, which talked a lot about how the future of buying will involve much more influence from our social networks. How easy decisions will be when we can see what our friends chose and how they felt about it.

But what if my friends aren’t there yet? Just a month ago I had to explain to a good friend what Foursquare was. And even though everyone has heard of Amazon and Yelp, very few of my friends have ever written a review about a product or place.

Now, I haven’t either, but that’s about to change. I want to start a movement to encourage people to give back to the Internet that gives so much to them. I’ll start with myself. I plan to leave more reviews across the web, even if it is as simple as leaving a tip on Foursquare or attaching StickyBits to barcodes.

How can I convince my friends and others to do the same? What is the motivation behind leaving reviews? How do we encourage this on a broader scale? If not for my personal benefit, but for that of our clients as well?