Hmm...from my experience....it's good for interaction designers to understand interpreting UML written by Product Managers, Business Analysts, Engineers, or other stakeholders in the project. For example, I worked at a software company where our product teams were spread out in three different continents - where lot of team members did not speak/write english fluently, and using UML kind of helped (it helped communication between designers, engineers, PM's and etc using common symbols and lines created from UML).
Here were some problems we encountered: we did find out later in the game, learning UML is not that easy - it has bit of learning curve and tools were very expensive (although there are some opensource/cheaper ones now).
Trend I've seen in my job (most in large enterprise software companies), more and more engineering architects, product managers, and developers are using UML with their specs. So if you want to speak their language, then you should enough of UML to communicate and comment.
Implementing UML to your design is your choice - but ask your self this: do you have enough understanding of UML? have proper tool? and will people you work with adapt it? In smaller software projects, just my personal opinion, might be an overkill. But for large projects, it might be worth exploring.
In side note: yes OVID is quite old, but for last few years IBM consulting have been trying to pitch their User Engineering process that use UML quite a bit. Not to mention, IBM bought Rational Rose. Few years back, at Ease of Use conference at IBM research center in california, they gave tutorials on using UML with their user engineering process. My feeling was that, for most non-ibm participants (lot of them were designers with no engineering background) were overwelmed with UML.