We have been using Erlang on our team at Yahoo! for the last 2 years, during which time we have been advocating for its official support. While it is easier, and possibly more fun, to be able to mandate Erlang as the prefered technology, it is more realistic to be confronted with complex integration scenarios. In this talk we will present several case studies of integrations we have done as well as the challenges we have faced in justifying our choices. In order to deploy Erlang effectively we have had to interoperate with company standard stacks, as well as various legacy systems in written in various other languages.