Whose to say that they will not become self aware and act together as one. I would compare them to an ant colony, all striving as one entity.
I watched a show on the Discovery channel about just such a possibility. If nano technology is perfected it could raise a building, and by the same standard, deconstruct said building.
I don't think we're ready to handle such a thing.
Whose = Who's
This was a subject of a Star Trek TNG episode. The Nanites develope self awareness and take over the ship IIRC.
"Whose to say that they will not become self aware and act together as one."
That - and they "eat carbon dioxide - a global warming gas".
Let's hope they don't get the idea of "I know how we can solve global warming" and decide to cover the planet!
My alma mater developed a nano pump - it can flow with the blood through a person's veins. I forget exactly what it was used for - either to sample or to give small amounts of a drug to a specific area.
Pretty amazing stuff.