Really? A string? In half?
Yes. This is not a hoax. Just old fashioned science.
The ingredients necessary are simple: string, acetone and a match.
We initially assumed this was a result of the acetone, the magical ingredient in many other fringe hacks of this nature. But the acetone here is simply an agent for flame. (Hint: look to the Related Videos on the right to see the other applications.)
The clean break in the glass occurs when the exact ring of heated glass comes in contact with the cold water. Thermal shock slices the bottle in half.
If the act isn't magic enough, practice this on several bottles to craft yourself a set of mod glasses.