The fate of Mendeley and Connotea should serve as reminders of the dangers of relying on free services. The users’ needs and desires come secondary to the real customers — in Google’s case, the advertisers; in Facebook’s case, those purchasing data and access to users. When a company has no business model, then the terms of service they provide can turn on a dime when one comes along. Think of the recent Instagram furor, or all the companies built around providing services for using Twitter, and how doomed they are now that Twitter is shutting down the very openness that made them what they are today.

It’s far better to pay for a service that’s critically important to you than to rely on one where you are not the sole focus of the company providing that service. If you’re the paying customer, then the company’s health is based on keeping you happy. Mendeley and Connotea are showing us that a free service can at any point be shut down or suffer drastic changes with little regard for the user’s best interests. If you’re an altmetrics startup that was planning on building a business around Mendeley or Connotea bookmarking as a key measure of researcher interest, what do you do now?