No menu exists, and what looks like the taskbar, the context menu tells you, is actually an activity bar. In other words, instead of displaying applications, the activity bar lists what KDE developers call 'containments' -- workspaces that define how widgets are arranged on the screen. The activity bar is a mechanism for switching between activities.
I've been meaning to write up my own first impressions from scratch but honestly, in the half-hour or so that I played around with Plasma I couldn't find a screen-grabbing app show you what it looks like.
As you'd expect with any KDE-based distribution, Plasma is fairly heavy on the eye candy -- despite this it seemed to run reasonably quick on my aging Eee PC 901. My biggest hurdle with it was that I wanted to quit the "Newspaper" containment thingy to free up space on my screen, but um... couldn't figure out how.
I'm all for innovation in small-screen user interfaces, so it's definitely worth booting up Plasma from a live USB stick and having a play. You can download your complimentary copy right here!