Algae Can Carry Cargo
Steve Nixon writes "Recently, a team of scientists devised a way to make single-celled algae bear loads over distances of several centimeters--a tactic that the researchers say could prove useful in tiny machines. Algae and other single-celled organisms power their movements with molecular motors. 'Scientists have long coveted these motors for use in micromachinery,' notes chemist Douglas B. Weibel of Harvard University.
Microscopic DNA robots will be delivering sublime advertising messages. The whole concept would be of course garbage since you wouldn't be able to see them anyway, but it wouldn't stop the bastards convincing potential investors in spamming you. You know who am I talking about, the shady 4.22% :)