It allowed you to fill out a detailed job dossier about your position at a particular company, and then users could purchase the dossier; RungJump would take a cut, and the person who wrote the dossier would get the rest. It was kind of like a premium version of Glassdoor, where the expectation was the dossiers would contain more candid info.
Here are some of the problems I ran into:
* You had to solve the chicken-and-egg problem twice. Once to attract insiders and once to attract paying users. It was hard. I would imagine The Lobby will face the same problem, and in fact possibly even to a larger degree, since my dossiers were "write once and then forget about it" whereas The Lobby is scheduling phone calls, so the insiders need ongoing availability.
* Quality control is hard, because of the information imbalance. Who's to say whether a particular insider is actually giving you information that's worth the price of admission? If you knew enough about the company to call B.S., you wouldn't be paying for the service. I would imagine The Lobby will face the same problem.
* Employers really, really do not like their employees being paid on the side to dish about the company. And employees were (rightly, I think) hesitant to potentially put their jobs on the line to make a little side cash. In fact, the more exclusive and well-paying the job, the less likely it was worth the risk for insiders to participate. I would imagine The Lobby will face the same problem, especially since it's starting out with a narrow focus on "elite finance" roles, and promising anonymity only goes so far.
* As Deepak noted, it can be hard to persuade job seekers to pay. One big reason for that? If you don't have a job, money is probably tight. And when your target demographic is, in general, hard up, it can be a very difficult business model to get right. The Lobby is trying to get around this problem by partnering with colleges who subsidize the costs; I think that's a smart move, and I wish them luck!