People love to be the first person to do something. Anything. Look no further than those annoying posts on blogs and online news stories where someone simply writes, "FIRST!" because they're celebrating being the first person to comment. Or watch any news program and see how they will report the detail of any minor celebrity in the off chance that it leads to a bigger, more exciting story. Then they can run ads that say, "We were the first news team to bring you the story of Jennifer Aniston's new puppy."
Now, imagine if you could get paid to be that cool, hip person who gets try products and services before anyone else? When everyone else is claiming to have discovered this awesome new technology gadget, you can say, "Oh, that? Yeah, I tried it out months ago."