Telenor, one of the top 10 wireless telcos in the world, has posted a great story about NOSQL to the Rescue. In their own words:

This is the story about how we solved our problem, and then some more, by introducing NOSQL solutions into Telenor
- Sebastian Verheughe and Katrina Sponheim at the IASA Norway meetup.

Telenor: How NoSQL, Neo4j and SOLR paid off for telenor