What is the fine-grained topic of the following text: Intended initially as a mechanism to reduce the cost of phone service for low-income customers, the bipartisan Lifeline program has worked in lockstep with telephone providers and consumers to increase the uptake in phone service throughout the country and has kept pace with changes in technology as the U.S. moved from a wireline world to one where the number of mobile devices and services now exceeds the population to a recognition that broadband internet is an essential communications service. Only return the topic.
The Lifeline program's role in promoting phone service and adapting to technological changes in communication.