According to a Yahoo! research scientist, that money might be better spent elsewhere.
Which means if you were thinking about leveraging your millions of followers for personal gain, maybe rethink that strategy.
And of course, the smaller the fish, the less it costs to reach them. There is probably some point, far after the $10,000 for Kim Kardashian, not so far after bloggers earning 74 cents per click, that your value as a conduit for information/ads becomes zero.
If marketers do decide to target thousands of people with just a small circle of friends, you can cross “twitter spokesperson” off your list of possible job descriptions. Jarvis does note, though, that Watts found that a combination of mass marketing and long-tail (Kim Kardashian and you) is effective.