RealtAsia was originally prototyped in 2010 with an early version of BuddyPress (a WordPress social add-on) but it proved too difficult to customise and the final application was simply too resource hungry to be ready for primetime
The re-write was created as multiple smaller applications primarily consisting of custom-made oAuth2 based API & Application servers. It is supported with a custom queue module for processing notifications & emails, a "ticker" module for processing newsfeeds and a websocket server for live updates
With the exception of the websocket server, everything else is powered by PHP, specifically, Kohana.
RealtAsia's API server is built with scalability. It has an extremely small memory/CPU footprint. It can process 10k authenticated requests at a concurrency of 100 in a few seconds on the lowest hardware specs (1GHz single Core, 512MB RAM).
Behind the scenes, MongoDB powers the social network, property listings and analytics.
Unfortunately, RealtAsia was never brought to market and currently, the entire application is scaled down into a single server - serving little or no traffic and is hidden away from search engines.