Just to clarify on this subject: the 83(b) election applies to stock options where early exercise is involved. Not all companies permit early exercise.
Also, Peter Thiel always told his portfolio companies to allow 83b elections. It's smart for the employee and the employee. I guess it's a changing of the guard from the Founders Fund types to the YC mania today.
Founders and key early hires, who may be receiving restricted stock (not options), are in a different camp because they're receiving stock, not options.