If you've ever wondered what's being done with Erlang, we've got you covered.
This Stack Overflow question will start to give you a good idea:
Amazon uses Erlang to implement SimpleDB, providing database services as a part of the Amazon Elastic Compute Cloud (EC2).
Yahoo! uses Erlang in its social bookmarking service, Delicious, which has more than 5 million users and 150 million bookmarked URLs.
Facebook uses Erlang to power the backend of its chat service, handling more than 100 million active users.
T-Mobile uses Erlang in its SMS and authentication systems.
Motorola uses Erlang in call processing products in the public-safety industry.
Ericsson uses Erlang in its support nodes, used in GPRS and 3G mobile networks worldwide.
The most popular open source Erlang applications include the following: the Ejabberd system, Wings3D subdivision modeler, the CouchDB database, the MochiWeb library, and RabbitMQ, an AMQP messaging protocol implementation.
And, as Jose Valim points out in his lecture, Whatsapp – a free instant messaging program that runs across iPhones, iPads, Blackberries, and Androids alike – uses Erlang. Amazingly, there are 2 million connections on a single node, running from only 10 machines.
That’s the power of Erlang!