New definition, kind of winging what this should look like but here goes:
stacktrap (n) – a product or service from a company that lures you into a set of additional products or services, locking you into that company and limiting your use of other competing services
similar: lock-in, product lock-in, data lock-in
examples:  The new iPod is a stacktrap for all your music and video for Apple.  The new Facebook Home phone is a stacktrap to keep all your contacts and messages on Facebook.
stack trapped (v; past tense) – to be tied to a particular set of product and services from one company, limiting a person’s ability to use a competing set of products and services.
examples: I have my email and documents stack trapped Google. I have my music and videos stack trapped in Apple. I can’t decide whether I should get an iPhone 5 or Nexus 4 device.