From the page you're linking to:
Hello! Before you can sign in and download Joost, you need an invitation from another user.
Hello! Before you can sign in and download Joost, you need an invitation from another user.
to correct this, i can give invites to anyone who wants,
My address is denis.papathanasiou (at-sign) gmail.com
Bit Bitdiddle
bitdiddle@member.fsf.org
fedorov@rutgers.edu
Cheers, R