Unlike the blog states, it seems that WSJ is, in fact, using "actual, realized returns" as evidence.
http://www.wsj.com/articles/andreessen-horowitzs-returns-tra...
* How did Sequoia end up as the only VC that made money from Whatsapp? It certainly wasn't an accident.
TL;DR: Sequoia didn't get that deal just by random chance.
Jan and Brian were uninterested in VC or business relationships to the extent that they were impossible to contact. There was no address on their website. There were no contact details. They ignored inbound emails. There was no signage on the building. They ignored press emails. But Sequoia knew they were in Mountain View and literally had partners walking the streets doing a physical search for them in order to initiate that contact. That's a pretty amazing effort.
Additionally, Sequoia have an internal tool called Earlybird they wrote themselves that monitored mobile app stores, which is how they noticed that WhatsApp was doing so well despite the fact that it had not taken off in the USA specifically. They relied on hard data collected systematically, rather than waiting for hot Bay Area startups that the VC's friends were using to turn up on their door.
And finally Sequoia had a great name that Koum associated with success.
There's a lot of great info in this video. I love WhatsApp partly because it violates so much received valley wisdom and yet has been so successful.