If you need your software system to serve millions of user, you should think about clouds.
We offer development of software systems ready to work in clouds.
And even if you prefer more general way – using infrastructure-as-service clouds, like Amazon or Rackspace, you still need the software system to work with distributed datastore. (As otherwise datastore would be a battleneck of the whole system.) For such cases we offer software systems based on Apache Cassandra – a distributed datastore, initially opened by Facebook. Here we have developed our own advanced Object Relational Mapping library, which makes it easy to store java objects in cassandra.