In the interest of objectivity, none of the links below are affiliate links, and none of them have paid or provided any other consideration for their presence here. These are legitimate companies with business models that allow you to get paid for a wide range of activities.
Sites like ReferEarns, Zyoin, Who Do You Know For Dough?, and WiseStepp connect employers with prospective employees, many of whom are already employed and not actively job-hunting, via networking - the people who know these qualified candidates. Rewards for referring a candidate who gets hired range from $50 on up to several thousand dollars - not chump change.
Connect suppliers with buyers.
Referral fees are a common practice in business, but they haven't been used much in online networking sites because there was no way to track them. Sites like Salesconx,InnerSell and uRefer now provide that. Vendors set the referral fees they're willing to pay (and for what), and when the transaction happens, you get paid. uRefer also allows merchants to set up referral programs for introductions and meetings, as well as transactions.
