I’m not sure which role you’re thinking about applying to specifically but because I know about the engineering process the best I’ll speak to that.

Where they recruit?

You can always apply to Facebook on its website or reach out to anyone at the company who you know and they would be ECSTATIC to ‘refer’ you to Facebook because of its generous referral bonus. If you know you want to apply to Facebook, this is probably the best way you can proactively get an interview at Facebook.

For senior engineers: Facebook recruiters always goes through tons of profiles on LinkedIn (and other recruiting websites). They reach out to senior engineers specifically working at companies they’ve known about. To stand out you’ll want an online profile (probably LinkedIn) that says you’re a software engineer with your experience and your degree if it’s relevant.

For university graduates: recruiting begins super early, like for interns sophomore / junior year which then convert into full time offers. There are specific ‘target’ schools that Facebook goes to for career fairs. Some common schools are like: University of Waterloo, Georgia Tech, Berkeley.

How they recruit?

They’ll reach out to people specifically through email or LinkedIn or will connect resumes at career fairs.

How strenuous is the interview process?

It usually starts with a phone screen in which they make sure you actually know how to code. The guideline is you’ll generally make it past this if you have > 25% of passing the interview onsite.

The onsite there’s 3 kinds of interviews:

Ninja (coding + technical skills)
Jedi (behavorial)
Pirate (code design)

Definitely practice algorithms / problems before you head into your interview, especially if you’re out of practice.

Who are they looking for?

Energetic, smart people who want to make the world more open and connected.

Good luck and I hope your dream is realized!

@anonymous71 great answer. I just want to add that Facebook comes to University recruiting fairs.

I was on the Stanford campus the other day at one of the career fairs where Facebook was actively recruiting CS students. I suspect this is also the case for other Universities which also have strong CS programs.