But YouTube also is a part of Google’s core advertising business, which is still more than 15 times the size of its cloud operations. That ad business has been decelerating lately. Total advertising revenue came in at $37.9 billion, which was up 17% year over year but still fell shy of Wall Street’s forecasts. Ad revenue for the full year rose nearly 16% to $134.8 billion—a notable slowdown from the 22% growth logged in 2018. Google still accounts for nearly one-third of the world’s digital ad market, according to eMarketer, but it faces growing competition from the likes of Facebook, Amazon.com and others. Alphabet shares fell more than 4% after hours following the report.