I've got a client with several WordPress hosted websites. Recently, I have been talking to them and they told me their long term idea of their work.
In future, they want to build a community of like minded people that can potentially have thousands of users. Now they have shown me what they have in mind particularly. They want a Facebook like social network with being able to make groups that people can join, posts statuses and have a hashtag tagging and filtering. For example, when someone posts a job opportunity with a #JobOpportunityItaly or #Italy so when you click on #Italy to get a filtered search with job opportunities, announcements and every post with hashtag #Italy.
They have sent me the link to one similar social network and it is Impact Hub. It is subscription based network which has all the features which I specified above. They also want it to be hosted by them and they want to build a social network of like minded people and it can potentially have thousands of people using their network. It would be based on a monthly subscription as well.
They want a long term solution so they don't want anything like a forum or a WordPress plugins like BuddyPress or similar.
What I need are recommendations for social network system solutions either paid or free community editions, free systems, etc. Also, should I go with a custom solution built completely custom or upon an MVC framework or any other ideas. I'm open for all recommendations.