i don't think they need to for quite a while. >> that was ben thomson and benedict evans. well, tesla has set a goal to deliver 35,000 electric cars this year. we'll talk about that and their latest earnings in an exclusive conversation with c.e.o. elon musk. >> welcome back to the best of "bloomberg west." i'm emily chang. well, tesla is riding high on an increase in model x deliveries. they reported fourth quarter revenues of $615.2 million, up 101% year over year one thing missing from the report was details about a battery gigafactory. our "in the loop" anchor, betty liu spoke with musk about why they didn't disclose more details about that factory as part of their release. >> there just wasn't enough time to get into the details of the gigafactory on this call. we had a lot to talk about with the rest of the business. just talking about fourth-quarter results and expectations in the near term for this year. whereas the gigafactory is more of a long-term development over the next three years. it deserves its own call. we're going to do that call and answer questions in

benedict evans talked about it, 10% of facebook for whatsapp.plication, 32 engineers at whatsapp. we talk now about, jed kleckner with us of delivery.com. mobile phone changes everything. your perspective on whatsapp? >> have any of you, if you could recall a company called icq. >> messaging. >> it was required by aol, aol had instant messenger. i am a user of whatsapp. facebook already has a standing product. when you look at what a wild is the messenger -- at what aol instant messenger and icq is, nobody knows. think there is still a mystery, 72% daily use, this has the same doubts? >> i am an optimist when it comes to technology. i question what this will become over time. see people coming back, we have seen from the likes of twitter, easy come, easy go. what is the key to success? >> you have to figure out if whatsapp will create greater loyalty to the facebook platform. do they have a platform people want to use, they have to buy things to get people to use it? lunchram was eating its and photo sharing, are they defensive or moves they hav

benedict evans here with me in the studio in san francisco. m glad to have both of you on this, because you are two of the foremost anchors on what is going on in mobile. benedict, i have to ask the question about the number. whatsappwhatsapp is worth it? >> was instagram worth $1 billion or worth 1% of facebook at the time? the question for mark zuckerberg is around maintaining share if engagement and share of activity. it is a significant percentage of facebook. whatsapp is taking a big chunk of people who should have been using facebook and they are all using facebook first. the question for him was, do you just sit and try to compete with that? they would be looking at facebook messenger or the numbers for that for the last year or two years. would you say, this is a really great mobile conversation product and should be part of facebook? >> looking at the landscape of mobile messaging apps out there, you are in taiwan, you have seen the rise of viber. do you think this is worth it? >> i tend to think it is. the price per user is very reaso