Hi,
To build your social media networking website like facebook you need below features:-
Members will have their dynamic profile where they will be able to upload pictures, videos, music, photo album also will be able to list their offered products to sell.
Members will be able to search other member's & add them as their friend also can search & browse offered products by different members and can have private messages and chat with them.
Members will be able to see the members who had visited their profiles recently, can manage ordered products, inventory, payment, shipping etc. Members will be able to like, comment on the status/images/videos / offered products etc of other members.
In addition, members will be able to post status, photos, videos, offered products and can share them with other friends on the website. Users can create groups & events. Whereas system admin will be able to manage all aspect of the website like a member's group's, file's, images, videos, polls, banner, contents, etc.
Let me know if anything needs to change in my understanding of the requirements.
Just let me know one question:-
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Do you want seller directory like facebook?
Let me know your available time for detailed discussion?
Regards,
saheli