Many file sharers have claimed that they only use the networks to find deleted music or music unavailable to download legally. Others have said that file sharing has led to them buying more music, and like radio, it's in fact promotional. Research has demonstrated time and time again that any promotional benefit derived from illegal file sharing is more than offset by those who buy less music because they can get it for free. Downloading or uploading music is illegal regardless of whether or not it's available commercially.