Would
this be a duplicate if it were on-topic? If so, I'll comment with a link. If not, I'll generalize it and vote to reopen. Actually I'm not really sure it was off-topic, because they may have just meant that they were using KDE 4 Plasma Workspaces on Ubuntu (or, well, on something) rather than that they were using plasmaLinux, which I don't think was ever very popular.