Facebook and Google's dominance in online ads is starting to show some cracks

Chief Operating Officer, Facebook, Sheryl Sandberg

Getty Images

Facebook and Google's long-held dominance in the digital ad market is showing some more cracks after a strong report from Pinterest Thursday.

Pinterest reported a whopping 62% year over year revenue growth in its second quarter earnings release Thursday, edging into the duopoly's turf. The dominance of the digital ad giants was already showing some weakness on the heels of strong ad revenue reports last week from Snap, Amazon and Twitter.

While ad revenue at Facebook and Google still dwarfs that of its peers, coming in at $16.62 billion and $32.6 billion in the second quarter, respectively, smaller players are showing they can still gain market share. EMarketer predicted the duo would lose their combined advertising market share in 2019 as global digital ad spend is expected to rise to $333.25 billion.

Strong reports from smaller advertising players shows there is still an appetite from marketers to diversify their ad spend across platforms. New advertising offerings could also be luring in businesses. Snap introduced non-skip commercials in its shows through its new "Snap Select" program, for example. Amazon and Twitter executives both told analysts on their earnings calls that new and improved product offerings overall are giving advertisers more of a reason to advertise with them.

Following just behind Pinterest's growth rate was Snap, which reported a 48% increase in total revenue from the prior year, coming in at $388 million. Amazon reported 37% year over year growth in its "other" revenue category, which primarily reflects advertising. Revenue for the segment was $3 billion in Q2, Amazon reported. And Twitter said it grew 21% year over year, reporting Q2 advertising revenue of $727 million.

Meanwhile, Facebook grew its ad revenue 28% compared to the previous year's quarter and Google grew 16%. Google's ad revenue growth had been a concern for investors in the first quarter, when it reported just 15% growth compared to 24% during the same period in 2018. At the time, Google CFO Ruth Porat partially blamed product changes in YouTube for the slowdown, but said in the second quarter that the video platform had been a big growth driver in recent months.

Subscribe to CNBC on YouTube.

WATCH: How Facebook makes money by targeting ads directly to you

Read More