6. A method comprising: receiving, by a computing device, a signal from a first stage recognizer based on recognition of an acoustic input signal and classification of portions of the acoustic input signal into different classifications using a first speech recognition algorithm, wherein the first stage recognizer is configured to recognize the acoustic input signal in an always on mode, wherein the different classifications correspond to different topics of interest, and wherein each classification is associated with a list of keywords for its corresponding topic of interest; activating, by the computing device, a second stage recognizer upon receiving the signal in order to recognize the acoustic input signal, wherein the second stage recognizer uses a second speech recognition algorithm that is different from the first speech recognition algorithm, and wherein the second stage recognizer recognizes the acoustic input signal based on a particular topic of interest that is determined, by the first stage recognizer, to be discussed in the acoustic input signal; evaluating one or more potential responses to the recognized acoustic input signal; if at least one response in the one or more potential responses is deemed acceptable, outputting the at least one response to a user that originated the acoustic input signal; and if no response in the one or more potential responses is deemed acceptable, refraining from outputting anything to the user.
6. A method comprising: receiving, by a computing device, a signal from a first stage recognizer based on recognition of an acoustic input signal and classification of portions of the acoustic input signal into different classifications using a first speech recognition algorithm, wherein the first stage recognizer is configured to recognize the acoustic input signal in an always on mode, wherein the different classifications correspond to different topics of interest, and wherein each classification is associated with a list of keywords for its corresponding topic of interest; activating, by the computing device, a second stage recognizer upon receiving the signal in order to recognize the acoustic input signal, wherein the second stage recognizer uses a second speech recognition algorithm that is different from the first speech recognition algorithm, and wherein the second stage recognizer recognizes the acoustic input signal based on a particular topic of interest that is determined, by the first stage recognizer, to be discussed in the acoustic input signal; evaluating one or more potential responses to the recognized acoustic input signal; if at least one response in the one or more potential responses is deemed acceptable, outputting the at least one response to a user that originated the acoustic input signal; and if no response in the one or more potential responses is deemed acceptable, refraining from outputting anything to the user. 11. The method of claim 6 , wherein the acoustic input signal is received through a network from the first stage recognizer.