Analysis of information sources in references of the Wikipedia article "David Karp" in English language version.
Sometime in 2006, we had a couple of weeks between contracts and said 'Let's see what we can do, let's see if we can build this thing', and we threw together the first working version of Tumblr.
Over the next few months, we kind of pieced together what became the first version of Tumblr which launched in February 2007.
It took about six months before I just gave in and said 'Alright, I'm pissing off my clients, we're not returning their calls, Tumblr seems to be where our hearts are, let's go for it.'