The following is a list of online services that currently offer some on-demand music streaming of full-length content over the internet as a part of their service without the listener necessarily purchasing a file for download. one might compare this type of service to internet radio. many of these sites have advertising and offer non-free options in the style of an online music store. for a list of online music stores that provide a means of purchasing and downloading music as files of some sort, see comparison of online music stores. many of both types of sites offer browsing by song title, artist, etc. that amounts to a form of online music database. see also comparison of online music lockers.