A carbon nanotube is a cylindrical carbon molecule about thousands of times thinner than a human hair with unique physical and chemical properties. It is 100 times stronger in tensile strength than an equivalent weight of steel; has electrical conductivity similar to copper; and thermal conductivity similar to diamonds.
Nanotubes is one of the frontier areas of materials science. These are new materials with unique properties. Their applications are being explored. They have much potential if their unique properties can be married to the right applications.
Most consider their current commercial status exploratory.