What is the topic sentence of the paragraph below?
computers and the internet are merging a variety of communication and entertainment technologies, making them accessible from a single location. landline telephones are facing competition from more affordable voip and video conferencing options. radio stations offer streaming audio for those who wish to enjoy music and talk shows from their computers. television stations offer digital downloads of series episodes, and cds are quickly being replaced by internet-based digital music files, available for individual purchase. one has to wonder if eventually, radios, televisions, and traditional telephones will go the way of the phonograph.