Which came first, the internet (ARPANET) or YouTube?

the internet (ARPANET) came first, by 36 years. The first message was sent between two networked computers.

Side by side

the internet (ARPANET)

On 29 October 1969 a team at UCLA tried to send the word "login" to Stanford. The system crashed after two characters, so the first message ever sent over the internet's ancestor was "lo". By the end of that year the network had four nodes. The internet is twenty years older than the Web, and confusing the two is the single most common error in this whole subject.

YouTube

The youtube.com domain was registered on Valentine's Day 2005, the first video — "Me at the zoo", 19 seconds of a co-founder at San Diego Zoo — was uploaded on 23 April, and the site opened publicly in the winter. Google bought it in November 2006 for $1.65 billion, about twenty months after the domain was registered. It is younger than Facebook by a year and older than Twitter by one.