Business is all about competition. So it's no surprise that the business world has its share of legendary rivalries: FedEx and UPS, Home Depot and Lowe's, Coca-Cola and Pepsi.

Arguably, the largest and most significant match is a newer and less famous one. It's a battle for the digital advertising market and sets Alphabet (GOOG 0.82%) (GOOGL 0.72%) against Meta Platforms (META 1.05%). Here's a closer look at these two contenders to see which is the better buy.

Stock chart in front of $100 bills.

Image source: Getty Images.

Meta Platforms

First things first: The digital ad market is enormous. Some estimates place the global digital advertising market at nearly $680 billion and growing. 

This sprawling marketplace is lucrative, particularly for Meta Platforms, the parent company of Facebook and Instagram. In its most recent quarter (the three months ending on June 30), Meta reported $32 billion in revenue, with $31.5 billion, or 98%, coming from ad sales.

The company sells ads across its network -- on Reels, Stories, feeds, and placements on Facebook and Instagram. What's more, the company offers Meta Ads Manager, a tool that allows customers to build and oversee ad campaigns.

Meta's greatest selling point for its ad placement is the size of its audience. It boasts more than 3 billion monthly active users (MAUs) -- fully 37% of the global population.

Analysts expect Meta to grow sales almost 13% next year to $149 billion. Meanwhile, earnings per share (EPS) are expected to rise 24% to $16.66/share.

Alphabet

Like Meta Platforms, Alphabet claims an impressive slice of the digital advertising pie. In its most recent quarter (the three months ending on June 29), Google Advertising generated $58 billion in revenue.

Google Advertising includes Google Search, YouTube, and Google Network ad revenue. Google Search, which generates more than 73% of Google's ad revenue, sells targeted ads on its Google Search results page. Alphabet's YouTube segment (13% of overall ad revenue) sells video ads on its YouTube Red (online video app) and YouTube TV offerings. Meanwhile, Google Network ad revenue (14% of overall ad revenue) comes from ad placements on Google Shopping, Gmail, Google Maps, and other applications.

It all adds up to a river of ad revenue for Alphabet -- and nearly double what Meta generates. In addition, Alphabet has a sizable cloud services business that generated $8 billion in revenue in the last quarter alone.

There are, however, trade-offs to Alphabet's massive size. For example, growth is more challenging. Analysts expect Alphabet to increase revenue by 11% next year to $339 billion. By any measure, that's still remarkable growth but slightly slower than Meta's expected 13% growth.

Is Meta Platforms or Alphabet the better stock to buy?

For investors seeking a pure play on the digital advertising market, the answer is clear: Meta Platforms, with its laser focus on digital advertising, is the way to go.

However, investors should be aware that Meta's focus could also become a weakness, particularly if the digital ad market takes a turn for the worse. Broader economic conditions remain challenging, with stubbornly high inflation, higher interest rates, and the possibility of a recession.

Those macroeconomic concerns might make Alphabet, with its larger size and more diversified business model, more appealing to long-term investors who want to dip a toe in the digital ad market, rather than jump in with both feet.

Either way, both companies are well-run and well-positioned to benefit from the skyrocketing growth of the digital ad market. As such, both are stocks that growth-oriented investors can consider adding to their portfolios.