An interactive advertising system run by Backchannel Media that was introduced in May at Hearst-Argyle Television’s WCBV-TV in Boston is set to expand, the New York Times reports. The test program, which lets viewers respond to programs and ads they’re interested in by using their remote controls, is going live on Hearst-Argyle’s WMUR-TV in Manchester, N.H., and Media General’s WJAR-TV, in Providence, R.I., the paper says.