Possible Mild Spoilers. Some people have been outraged that the TF's show up to earth as giant balls of nanobots (kind of) and are just made up of lots of nanobots. At some point in the film, the very flimsy idea is thrown out there that they evolved as a silicon based lifeform, as opposed to our carbon. In this handwaving kind of arguement, it makes sense that they would be made of nanobots, being the equivalent to our cells. Here's something exciting for you all, if you look close enough at a person, they're just made up of lots of little tiny cells! ZOMG! In a similiar way, Transformers are made up of lots of little ROBOCELLS - or Nanobots if you wish. Uh, that's about as far as I've come with this, I just thought some people might want to discuss it further or say things like "right on brother!"