RUM Concerns and Trends

Watching end user activity does present some concerns and pitfalls to watch out for, from privacy to portability and beyond. We’ve already considered many of the privacy concerns in the section on WIA, so be sure to check there for details on data collection.

Cookie Encryption and Session Reassembly

Some websites store session attributes in encrypted cookies. Unfortunately, obfuscating personally identifiable information may make it hard to reassemble a user’s visit or to identify one user across several visits. Whenever the visitor changes the application state (for example, by adding something to a shopping cart) the entire encrypted cookie changes.

Your development team should separate the things you need to hide (such as an account number) from the things that you don’t (such as a session ID). Better yet, store session state on the servers rather than in cookies—it’s safer and makes the cookies smaller, improving performance. This is particularly true if your sessionization relies on the information in that cookie.


RUM tools may extract content from the page to add business context to a visit record. While this is less risky than collecting an entire page for replay (as we do in some WIA tools), you still need to be careful about what you’re capturing.

When you implement your data collection strategy, you should ensure that someone with legal authority has reviewed it. In particular, pay attention to POST parameters, URI parameters, and cookies. You’ll ...

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