What do the numbers on bottom of bottles indicate?

I recently came across another chain mail, about the numbers below plastic bottles we use. Every plastic bottle  has a number (generally within a triangle) written at the bottom, ranging from one to seven. Now this Hoax Chain Mail claims that the number indicates how many times that particular plastic is recycled in reverse order.

In reality the number registered has nothing to do with the number of times plastic has been recycled.  It’s just the type of plastic which is used for that particular bottle. 5 is polypropylene and 1 is PET that is polyethlyene terephthalate etc etc. The numbers below is useful while sorting the collected bottles while recycling. In other words it is plastic identification number.

1 – PET, polyethlyene terephthalate
2 – HDPE, high-density polyethylene
3 – PVC, polyvinyl chloride
4 – LDPE, low-density polyethylene
5 – PP, polypropylene
6 – PS/PS-E, polystyrene / expanded polystyrene
7 – OTHER, resins or multi-materials

What do Those Numbers on the Bottom of Plastic Bottles Mean?

Google yourself if you want to read more. But please do not panic if you receive the same chain mail tomorrow.

Here is copy paste of that mail