Klout lets me know how my posts are doing in one simple to follow place. I can use business or personal accounts. For personal score if I get high enough they identify me as an influencer and I sometimes get gifts/trials/coupons for brands - this, I like.
I'm fairly active and followed on social media but I never get good giveaways. The best I've gotten is a couple cans of cider and some neutrogena, maybe Canada gets a bad deal. Either way, on the receiving end these didn't influence much in me. I tweeted about the cider because I didn't know you could maill it. Long story short, I'm not sure if Klout advertising leads to sales and I don't know if they can prove that either way.
On the business side I've seen our scores but facebook, twitter, etc. own that advertising pipe and have really gotten into giving me in-depth analytics on each of my posts and how they are doing. Instead of giving away free product I can just pay to advertise/promote posts on those platforms for way less money.
I think Klout sees this trend and is trying to add new, confusing features to stay relevant. I haven't tried them, they want me to use them, but I'd just stay away from it as a brand.