Complex sentence: Traditionally, stringers freelance for a period of time and then become employed full-time by a news organization, but with the collapse of the traditional newspaper advertising model and the emergence of the Internet, many stringers are becoming superstringers.
Split into simpler sentences: Traditionally, stringers freelance for a period of time, then become employed by a news organization. But with the collapse of the newspaper advertising model and the emergence of the internet, many stringers are becoming superstringers.