A lot of Mashable readers wanted Joost invites, and we've set up a system in the comments of the Joost post to ensure no one is left out.
I just invited another round of commenters, but for this to work, you need to reciprocate: if you received an invite from us, invite at least 5 more people from that thread and reply to their comments with "INVITE SENT" to keep things running smoothly. You may need to use a slightly different reply each time to avoid the dupe comments filter. If you want to be a hero and invite everyone, go ahead.
Joost users now have "unlimited" invites (displays as 1000 within Joost), so there's no excuse for not helping out the other Mashable readers. You can see the invite form by clicking "My Joost" in the interface.
Those who don't want to post their email addresses in the comments should use something like SpamBox to create a temporary email address, then invite yourself through the Joost interface.
PS. To avoid confusion, comments are turned off on this post. Go here to request Joost invites.