Content recommendation has become a big business, but it’s showing signs of its limitations. Yahoo, facing an uncertain future as a company, shut down its 2-year-old Yahoo Recommends service to publishers. It follows the shuttering of IAC’s nRelate as a standalone service to publishers. Two of Yahoo’s marquee launch clients, Hearst and CBS Interactive, have moved on and have signed with other vendors My6Sense and Taboola, respectively.