Whether you know it or not, if you have not opted out of Klout, it's created a profile for you. It's scored you. It's busy collecting data on you without your permission. It's making money off that data. In the future, your ability to get a job or participate in social functions may be impacted by Klout.
The new version of a very popular helpdesk suite includes the ability to retrieve your Klout score - how quickly your problem gets resolved when you log a complaint somewhere can now be determined by your Klout score.
To quote blogger Charlie Stross "If you aren't paying for the product, you ARE the product". You are being bought and sold. Klout is profiting.
But Klout has not proven itself a trustworthy partner in this respect - consistently surfing back and forth across the edges of ethical behavior.
Klout is able to survive and profit because:
1) People won't opt-out
2) People create Klout accounts (and don't close them)
These two things allow Klout to sell their wares (i.e. you) to sponsors. If people close their Klout accounts and opt-out of Klout scores in protest, then Klout will be pressured into changing their ways.
As I've written before, any company who is on a mission to impact people at a financial level (for example, their ability to get a job), a personal level (for example, does their DSL problem get resolved today or next week) or at a social level needs to be held to a high level of accountability, transparency and responsibility. So far, Klout has failed resoundingly.