"If you're an employee of a public company in the Bay Area with a stagnant stock price and you're really good at what you're doing, you have the chance to go down the road and get a lottery ticket [at a startup]," Mahaney told Re/code.
Yelp employees are getting offers from private companies at 1.5 to two times their current salary. As a result, the reviews company predicted it would only be able to increase its salesforce by 30 percent year over year even though it originally aimed to hit 40 percent. "I heard it clear as day from the Yelp numbers and call last night," Mahaney said. "They're not able to grow as quickly as they want to because of the unicorn bubble."
All companies are shelling out more and more money for talent. It's not necessarily a problem for the private startups whose profit matters less to their investors than their growth rate. With hundreds of millions or billions in venture, the likes of Uber, Airbnb and Pinterest can pay big staff salaries without it hurting them … yet.
Read MoreYelp shares plunge 28% after Tuesday's earnings loss
That's not the case for public companies with slower growth and greater pressure from shareholders to produce strong profit numbers. In a report on the earnings, RBC Capital Markets pointed out that the compensation competition could impact any and all "public companies in the Bay area with stagnant stock prices." In other words, Yelp may not be the last casualty of the unicorn bubble.
The other cause of Yelp's low 2015 revenue projections was the phasing out of brand ads to make way for local, native advertising. "Ads that play video or audio intrude upon the consumer experience," Yelp CEO Jeremy Stoppelman said on the call.
—By Carmel DeAmicis, Re/code.net.
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