Node is not going anywhere. It may not be cool anymore, but like the old cool kids (Rails, Java, Perl), it has achieved critical mass, and still has some killer features.
Node makes SOA (service oriented architecture) a lot easier. SOA is what all the cool kids are moving to, and is one of the reasons why it's so easy for big companies with lots of legacy code to switch to Go. Once your code is appropriately partitioned into services, it's easy to write a single service in Go, and go is a nice language for writing services.
That being said, Node is particularly well suited for consuming services. You'll necessarily have lots of client code written to consume and use these services from your webapp. So whenever you write a batch job or notification system or anything else that is primarily server side consumption of services or glue between services, node.js is a natural fit.
The other natural advantage of Node is that your business logic can run on both the server and the client. Your standard client-side web app (angular, backbone, ember etc.) has the bulk of the business logic in the client-side models. On the server side, the corresponding models are mostly just shims to the database, but they will also contain some business logic. If your code is written in Node.js, you just instantiate the client side model to be access the business logic.
The other killer feature for node.js has already been mentioned: combining both server and client side rendering with https://github.com/rendrjs/rendr or https://github.com/wvl/highbrow.