The company projects third-quarter revenue of $367 million to $373 million vs. current expectations of $383 million.
For the full year, LinkedIn expects revenue of $1.455 billion to $1.475 billion vs. expectations of $1.498 billion.
The site now has 238 million users, up 37 percent from a year ago.
As the social network has approached a saturation point among white-collar workers in the U.S., Weiner has pursued growth while turning LinkedIn into something of a highly-trafficked media destination.
In recent quarters, he has introduced blog posts by professional luminaries like Bill Gates in an attempt to draw web traffic—and with that, advertising revenue.
The company has three primary revenue drivers: talent and hiring solutions, premium subscriptions for users, and advertising. LinkedIn is trying to increase the number of ads appearing in users' feeds and recently hiked some of its fees.
—By CNBC with Reuters