At first LinkedIn also struggled to make money, trying to charge consumers a few bucks to use the site. Then it discovered the sweet spot. From 2012:
Rather than try to wring 20 bucks here and there from individual users, [CEO Jeff Weiner] refocused the company on selling a vastly more powerful service to corporate talent scouts, priced per user at as much as $8,200 a year. Today thousands of companies use LinkedIn’s flagship Recruiter product to hunt for skilled achievers. In human resources departments, having your own Recruiter account is like being a bond trader with a Bloomberg terminal—it’s the expensive, musthave tool that denotes you’re a player.