A fast and secure Social networking website similar to quora ,reddit

Users submit content( TEXT, LINKS) with heading (e.g. atheism, solar energy etc); Users can follow other users and headings => newsfeed/feed like quora/facebook; Users can like, report spam, comment on content; Submit content anonymously(like quora); Different link for each content by user (as in quora) ; Share content link to facebook,twitter etc. ; Profile, activity of each person like in quora/facebook (sign in/up ofcourse); Notifications like in quora,facebook; Different words turn into box which can be individually crossed (for example see pinterset search box.) Arrangement of: 1) SEARCH RESULTS FOR HEADINGS based on:- a) popularity( number of likes) to content b) rate of likes {how quickly content is being liked or likes divided by time} 2) In NEWSFEED : most popular content of topics, users followed by a user. Fast AUTOSUGGEST SEARCHBOX for searching from ever increasing lakhs of headings (also showing number of content/links for the topic like google earlier used to show number of results for a search) ; SIMILAR SEARCHES like google/bing show {showing number of links, text for each similar search } ); Searching people by their name/email id; Details of content submitted,searched,liked,commented, users activity etc ,so that I can easily analyse what’s happening and user behaviour on website. Captcha for sign up ; Deleting reported/spam content and account easily; Website should be fast for loading and searching IF you are confident and experienced in development of websites similar to quora, reddit, FB etc, you should be able to develop this as well. Let me know cost, time, languages and technology(database framework etc.) you intend to use keeping in mind hosting and development cost, scalability, speed etc. Preference to open source as its cheaper,customisable as well. Let me also know development of which feature/part will be most time consuming as well.