Hi,
I must say very interesting and challenging project. I have done some work on the similar project and did research on how Twitter search works on large volume. I would suggest lucene search library to create indexes over you data , and then implement algo to get appropriate results. Lucene works awesome with large volume if chosen indexes are good.
About me , I am ex-Microsoft employee and have 8+ years experience in software development and customization usingwide range of Microsoft technologies (C#, ASP.NET, MVC,WPF, Window form, Sql Databases, Azure, Sync framework etc.), Mobile technologies - Android, Xamarin and server side language node.js and Golang. Since i have previous experience in such applications, so I think it will help in this project, if selected.
About my previous work, you can visit my profile to see feedback from previous employer. Let me know, If you find me suitable for this project and share complete details. If you want more details, we can discuss over chat/ skype.
Regards,
Shashi