PHP-script that works like a sort of forum

Avg Bid (USD)
Project Budget (USD)
$30 - $250

Project Description:
(You can NOT use a readymade backend like Wordpress, joomla or similar.)

I'm looking for a script that kind of works like a forum.
This script is going to be used for a site where people can comment and discuss articles posted on other sites like and similar sites.

A user posts for example this article (URL):
The script should then grab the title(TITLE) from the URL, it should also make a small screenshot (if it's possible)
of the URL and the user should be able to change the title if he wants to and also add a description.

The script must check if the URL have already been posted, if it have been posted it will deny the user to post the URL and show the user
a link to the already posted article.

The comments should work like a forum where users can post comments and also quote and reply to comments.
I also want a "tumbs-up" and "tumbs-down"-function for all comments. (Max one upvote or downvote per user on a comment)

* The registration form
Users should be able to register/login with Gmail, Facebook connect, Twitter API, OpenID API and
They must also be able to register directly on my site without these services.
Captcha is a must on the registration form.
I also want the users to confirm their emails.

* The frontpage
On the frontpage I need a section with the 10 most commented articles of the last 10 days.
Also I would like the 10 newest articles to be displayed aswell.

* Search-function to search for words in the titles.

* Logged in users should be able to do "Thumbs up" and "Thumbs down" at the comments and the stats should be displayed at the site of the comment.
(Only 1 thumbup or thumbdown per comment per user)

* A quote-function is a must since it should work like a forum.

* Profile-pages for each member where you can see the persons last posts, postcount, thumbs up and thumbs down stats.

* The users would need to be able to change their pass, avatars and emails, so some kind of options-page or something would be good.

* A forgot-password-function

* A very short captcha must be entered to be able to post a comment or article, maybe like 3 digits or something like that.

* The script must check for dubbleposts, so the users dont post the same comment multiple times by clicking the "post-button" multiple times.

More features might be added later, I will pay for all extra features of course.

Skills required:
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