Professional Social Networking Starter Website development

General info:
NICHE SOCIAL NETWORKING WEBSITE with FACEBOOK-LIKE FEATURES

Similar Social Networks: Facebook, Twitter

REQUIREMENTS/FEATURES:
We need a Social Networking Startup Website developed.
We expect the developers to use a pre-existing Social Networking website script.

We have a clear vision of a niche Social Networking Website, with features much like Facebook or Twitter, such as:
News Feed
Friend feature
User Sign-up (Create a new account, or log in via Facebook, Twitter, guest posts with email address)
User's profile pages
Live feed on the homepage
Publishing posts (text, picture, video)
Comments on Posts
Like on posts
Like on comments
Messages and inbox
Notifications
Email Notifications
Search Bar/Engine
Etc...

We will discuss the features in much more detail with the developers we decide to hire. Our features are well designed and the developer will receive the full description of the website and the features.

*We have our logo and website mock-up designed, which will be the guide to the developer for the layout and the design of the website.*

-> We need a reliable developer with great communication skills, available via PPH messaging/email/Skype, a developer who will be available to work closely with us and perform the job to our requirements and deliver the work within an agreed timeline.
Hired developers will have to sign an NDA.

Please send tailored proposals WITH SAMPLES of your previous and relevant work!

---> PLEASE DO NOT SEND GENERIC PROPOSALS!

If we left anything out, please don't hesitate to send us questions.

EDIT: We expect the developers to use a pre-existing Social Networking website script.