Theme for an Interactive Website

Hello. I’m starting a site where users can post an idea and talk about it. This is nothing like kickstarter. This is just a collection of ideas and their summaries. The following features are required.

Post an idea
Browse through categories
Comment and share the ideas on social media

Create accounts and login
Registered user can follow fellow idea posters . Update alerts are sent to followers
Registered User can follow a specific category of ideas.

Top ideas page in each category
Sort ideas based on meta data and other information like location, date, capital, time required to execute, etc.

Please suggest few suitable themes. I intend to have atleast hundred categories where people can post ideas about. TIA