The blog entry is a bit sensationalist/typikal-amerikan, but I do agree with it - while there might not be evil intent behind, the thing certainly has a lot of potential for doing evil. Especially because it's massive google behind it, and there's a botload of sheeple who don't even know they've got google's toolbar installed.
Even if you ignore the "it can be used to hurt marketing" part out, there's imho enough ways this can be abused.