Q: Do you redirect them to login/register? How do they know they need to do that in order for their post to appear?I took a look at this tonight on a test site. The guest post is actually stored in a new table so it doesn't show up in any queues or anywhere else that a normal post would. If the guest registers an account then the post in the temp table is submitted as a normal new post would be so at that point it'd be subject to moderation & so on. If the guest does not create an account then the cron job will delete the post from the temp table after a set period of time.
Read more: Message posted by @Kevin
When users submit form. An overlay for login or register will be appear.