It takes 2 minutes and 5 seconds to create an account on WhatsApp.
Here's a slidedeck on the site useronboard.com which shows step by step the user journey.
Useronboard have a series of "teardowns" that show you step by step the onboarding process for new customers for a whole raft of well known sites from Vimeo to Netflix to Trello.
What I like about these "teardowns" is that they not only show the whole journey, screenshot by screenshot, but they also have running commentary about what is good or confusing.
If you're a product manager thinking about how to improve your onboarding experience, going through these teardowns will give you plenty of ideas of what you could test or improve.
Thanks to James Brooke for highlighting this excellent resource on user onboarding.