[PaulRobinson]

That's to reduce the pasta sticking together as it cooks.

[Clamchop]

In my experience, stirring within the first tens of seconds of submersion is enough and it won't stick together again for the rest of the boil. After it's strained is a different matter, but you might as well wait until then if you're going to oil it.

[slumberlust]

Doubtful because it just floats on the surface. Maybe ones you pour the water out?

[tonyedgecombe]

Which doesn’t really work as the oil and water won’t mix.