Depends on how you define top technology companies, but many large software companies (5000+ employees) uses UML as a part of their systems architecture deliver

Depends on how you define top technology companies, but many large software companies (5000+ employees) uses UML as a part of their systems architecture deliverables. Whether they are worth being designed will very much depend on who you ask. The architect who spends a lot of time on designing them will of course be very much in favor. He might feel they properly communicate his architecture. Certain business types might favor them, on a more simple account - they look deliciously technical and can be used to persuade a customer "we really know what we are doing". My personal opinion is that certain diagrams can be useful. In general though, way too much time is wasted on doing these diagrams, which aren't going to be at all representative of the end system. It's not a good communication tool, and it'll in most cases be hopelessly out of date just a few weeks or months into the project. UML also smells of a top-down approach where the star architect is sitting in an ivory tower handing down blueprints to lowly developers. That kind of approach goes against what I believe about successful software development. There's useful elements in UML and you definitely won't be worse off if you understand it. But I do not think it's in any way required unless your aspirations are to be developer /architect #2032 in BigCorp. But again, it'll depend on who you ask.