Site with basic Twitter functionality

Avg Bid (USD)
Project Budget (USD)
$1500 - $3000

Project Description:
Hi there!
I need to build a site that will be a slimmed down version of Twitter. It will have the following functionality:
1) There will be a list of ca. 300 items that users can follow
2) Each user can leave a comment/twit about the quality of an item
3) Each user can rank the quality of the comment provided by other users about an item
4) Each user can chose to follow an item and/or other users
5) Each item will have a “profile” page, with some automatically updatable data
I realize this is a somewhat limited information, more details will be provided once you submitted your offer and answer the questions below
In choosing the winner, I am focusing on experience in building the Functionality and Quality of Design – it has to be minimalistic, high quality and very user friendly.

To be considered, please provide specific answers, in this order to the following questions. Otherwise your bid will be considered as untailored spam.
1) Have you built “social network” sites before (facebook like, twitter like)? or sites with similar functions? Pls send a link
2) What programming language you are proposing to use? Will you be using existing modules or building everything from scratch?
3) Please demonstrate your high level understanding of whats required
4) Please provide your quote breakdown and estimate of time required.
5) Please also provide a quote with or without mobile comment posting capability
6) Please send not more than 3-5 links to sites you created that you think have very high quality minimalistic and easy to use design. Please do not send me a laundry list of all your works
Many thanks, I look forward to working with you on this project,

Skills required:
Graphic Design, HTML, PHP, Website Design
About the employer:
Public Clarification Board
Bids are hidden by the project creator. Log in as the employer to view bids or to bid on this project.
You will not be able to bid on this project if you are not qualified in one of the job categories. To see your qualifications click here.

$ 4200
in 50 days
$ 4550
in 40 days
$ 5000
in 60 days
$ 2500
in 15 days
$ 3000
in 45 days
$ 5000
in 60 days
$ 3000
in 25 days
$ 3000
in 90 days
$ 2500
in 25 days
$ 1500
in 1 days