It doesn't sound TOO unusual. Facebook apparently is the next Google, and there is no shortage of news about projects being started by ex-facebook engineers. Why would they leave, unless their equity package was pathetic?
The 20% set aside is usually reserved for "key hires" which is assumed to mean a flotilla of VP level people. If you follow the standard Silicon Valley VC-backed startup script, this means the VP of Product, the VP of Product management, the VP of Operations, and so forth. After the A round, engineers are usually looking at an equity maximum of 0.25-0.5%.
"be aware that founders get rich, late-stage employees get paid, and early-stage employees get screwed" is a great maxim. Unless your company is truly on track for a $1B acquisition or IPO, you are not going to be able to buy a house with an early-stage engineer's equity.
Oh, and... eventually you need to know C++, anyway. How it works these days is: employee #9 makes the site in Rails, or Python, or PHP. She makes $70K a year and 0.25% of the company. Eventually, she burns out and goes backpacking in Thailand for a year. Everything tips over, and you need to hire employees 30 and 31. They get paid $170K a year with no equity, cuz they are the only ones who know how to make it all work fast in C++.
Of course, employees #1 and #2 wrote the cool algorithm in Python, hired some other people to do the boring stuff, then let those people argue about Java on message forums while they argue about who gets the "California King" sized bed in the jumbo-jet. ;-)
The 20% set aside is usually reserved for "key hires" which is assumed to mean a flotilla of VP level people. If you follow the standard Silicon Valley VC-backed startup script, this means the VP of Product, the VP of Product management, the VP of Operations, and so forth. After the A round, engineers are usually looking at an equity maximum of 0.25-0.5%.
"be aware that founders get rich, late-stage employees get paid, and early-stage employees get screwed" is a great maxim. Unless your company is truly on track for a $1B acquisition or IPO, you are not going to be able to buy a house with an early-stage engineer's equity.