Online advertising giant Alphabet (NASDAQ:GOOG) (NASDAQ:GOOGL) reported fourth-quarter and full-year results after market close on Monday. The quarter's results featured more strong top- and bottom-line growth, fueled by advertising across its Google properties and network members' properties, as well as its cloud computing business -- Google Cloud.

While the overall financial results are worth looking over, the most notable takeaway from the report for investors is the company's first-ever disclosure of YouTube and Google Cloud revenue. Both businesses are seeing outsize growth compared with the rest of Alphabet's business.

Executives walking into Google's headquarters entrance

Image source: Alphabet.

Fourth-quarter financial results

Alphabet reported fourth-quarter revenue of $46.1 billion 17.3% year over year over. Total advertising revenue from online Google properties was $31.9 billion, up from $26.9 billion in the fourth quarter of 2019. Revenue from ads on network members' properties was $6.0 billion, up from $5.6 billion a year ago. "Google other" revenue, which now excludes revenue from Google cloud, increased from $4.8 billion in the fourth quarter of 2018 to $5.3 billion.

Earnings per share for the period were $15.35, up from $12.77 in the year-ago quarter.

The company's top- and bottom-line performance was mixed in comparison to what analysts were expecting. Revenue missed an average analyst forecast for $46.9 billion while earnings per share of $15.35 easily beat a consensus estimate for $12.53. This earnings-per-share beat, however, was because the company's fourth quarter of 2019 saw a 0% tax rate thanks to one-time items, including the resolution of multi-year audits, compared with an 11% tax rate in the year-ago period.

YouTube revenue is up more than 30%

Alphabet broke out its YouTube advertising revenue, which is included in its Google properties revenue, for the first time. YouTube revenue was $4.7 billion, growing 31% year over year. The streaming video service, therefore, accounted for 15% of Alphabet's Google properties revenue and 10% of total revenue.

In the company's earnings release, Alphabet notes that non-advertising YouTube revenue such as subscriptions to YouTube Premium, are included in "Google other" revenue, alongside hardware and Google Play app store revenue.

Google Cloud revenue is soaring

The company's Google Cloud revenue, formerly reported in Google other revenue, was $2.6 billion -- up 53% year over year.

For some context, that compares with Amazon.com's (NASDAQ:AMZN) cloud computing revenue of $7.4 billion during Q4. While Google Cloud is still much smaller than AWS, the world's largest cloud computing business, it's notably growing more rapidly than Amazon's cloud business. AWS revenue was up 34% year over year in Q4.