How can anonymous users be allowed to post while still maintaining content integrity? A little background: As you see on http://charlotte.ebayclassifieds.com, if you click 'post an ad' and then choose a category, you can fill out the form and submit content without having to sign up.  This is all done and managed by sending validation emails to the email address field which, when clicked, allow a user to manipulate their content.

Can similar functionality be achieved in Drupal. I don't mind writing a module, but before I do, I want to make sure I am not reinventing the wheel.

I have a Drupal based local classifieds site for my community at http://www.gastonia.com.  The site is growing in anonymous traffic, but few users are signing up to post. After a couple feedback loops with the community, almost everyone is saying that the one barrier to entry is having to sign up for an account, check email, validate, figure out how to navigate to post an ad, etc - indeed there are 7 steps necessary to go through before an ad actually gets published.  It's too much..

We have reworked the architecture to be able to get it down to two clicks - click to post, then click to save. More specifically, a user clicks on 'Add content' and the node/add form pops up (there is now only one content type in the new architecture); Then, when they are done, they click save.

Originally I thought about the Inline Registration module, but it is still in DEV and the logic really is not there to support if the user comes back to post again with the same email address (without loggin in). I could alter it, but then we are back to writing a module.

I also thought about Rules - could rules handle similar functionality as the ebayclassifieds site or what I am trying to do? It would all be based on an email filed in the node/add form (CRUD functionality).

What direction or recipe would you suggest to achieve the functionality? Of course the ultimate goal here is to allow anon users to post; create an account behind the scenes for future use; allow use of the anon form even for users with emails that already have accounts (and assign content accordingly.) all while maintaining the security (from spam, bots) that is afforded by having a user sign up and authenticate an account.

EDIT: 4/1/2013
Gisle Hannemyr has revived the Anonymous Publishing module which is very close to achieving the goals described here and in other posts. Please take part in the the thread to provide some community feedback as to how to make the module bug free and better:
http://drupal.org/node/1957644
I don't think this is possible with rules alone.

You need to alter the submission form in order to capture the verification email address, and you also need some logic to ban spammers and recognise returning visitors.

I am the maintainer of a project named Anonymous Publishing. It looks as if this module does what you want.

It still in development, but a Drupal 7 version has been used at several of my production sites without any issues. Please check it out.

You may also want to look at the answers under this question.