An SRV record is a DNS record, that is used to point a domain name to a third-party server and use it for a service different from a website. This can be a Voice-Over-IP server, a video streaming service, an instant messaging system, etc. When an SRV record is set up, you can specify an Internet Protocol which the domain will use and the port, that will be used to connect to the remote server. Furthermore, provided that you have a few SRV records for the very same service, you'll be able to set different priorities and weights for every single one of them, in order to distribute the load between several machines. Such a record allows you to use the same domain address or subdomains under it with different providers, so you're able to use it for various purposes even if you can't get all the services from a single provider.