Registered members of PhOnline receive a username and password that allows them to add their papers to the database.
Putting your papers in the PhOnline database will not only make them more widely available in the philosophical community. It will also give your work more exposure, potentially increasing its influence and even increasing the amount of feedback you receive prior to (traditional) publication.
Membership is open only to members of philosophy faculties (and faculty in similar departments, such as departments of logic or metaphysics) in accredited institutions of higher education.
The web generally suffers from a very poor signal-to-noise ratio. PhOnline will only be useful if there is some guarantee that papers listed here are of some minimal degree of quality, and fairness requires that there be some clear policy regarding membership. If you think you should be allowed to register but do not meet the condition just specified, you are welcome to contact the maintainer and make your case. Please understand, however, that membership is at the sole discretion of the maintainer of PhOnline and that the maintainer takes the signal-to-noise problem very seriously.
No. PhOnline only hosts the database. Your papers should continue to be placed on the web whereever they are now placed, e.g., on your personal site.
Not necessarily. You can, if you like, continue to list your papers on your own site as you always have. Or you can include a page from PhOnline on your own site. Visit Richard Heck's website to see several examples of how that can work. Information on including such a page on your own website is available once you register.