The name of this blog refers to a quality of good server software, it sits in the corner and just works. The fact that people forget about it, or at least take it for granted, is an indication of success. But silent software is not about software that is mute; servers should log copiously when asked to, and fail loudly.
"Just works" is a perception, not a physical characteristic. Lack of quality for a product can be defined as the gap between reality and expectations. It's just as important for a product to manage expectations as it is to manage the product itself. Especially new technology like speech recognition, where expectations can easily be set sky high. There is an interesting graph in Speech Server white paper showing how increasing CPU speed will improve recognition quality over the next number of years. The challenge for the next few years is finding domains where the current speech rec software can work well.