Are there any cloud based private Twitter-like services out there?
I am working for a client who needs a service like this implemented, but we don't have the time or budget to create one from scratch.
I am looking for something with a REST api where I can create an account on it from the master server, set an account to follow another account, post updates for accounts, and then get a feed of posts (sorted by date) from accounts that another account is following (like a facebook wall, or twitter feed). It would be great if it could automatically scale out to hundreds of thousands of users, with perhaps 50 000 daily posts being made.
I had thought about implementing this myself, but it seems like there are some tricky areas when it comes to having an account following a few thousand other accounts, or being followed by 10s of thousands of accounts, and generating the feed in somewhat realtime as posts come in.
I have found some services such as http://www.ning.com/ and http://www.socialengine.com/ but I'm not sure if they can do what I need, and they seem to be very focussed on having a website. This is for a mobile app so that is not required.
There are a few open source projects out there, but they would all require setting up/maintaining hosting (not a huge problem) and I'm not certain how scalable they are (the client requires it scale up to at least 100k users).
I'm sorry for the late reply. I hope it will be useful to others looking at this.
I had pretty much the exact same need as you, and ended up creating a full-featured solution after finding no other resources. The service is called Collabinate (http://www.collabinate.com). It provides a RESTful API that focuses on simplicity and ease of use, and currently leaves the UI completely up to you. It uses a graph database and algorithms in the backend, and scales quite well for your situation.