I chose this slightly controversial post title on purpose to draw a tiny bit attention on plasma-netbook.

As it seems there is no work done in 4.9 on the netbook part:
http://techbase.kde.org/Schedules/KDE4/4.9_Feature_Plan

I think the concept is very nice, but there has been barely any development this year. So my question: Is it dead?

The roadmap says they are at M3 out of four
http://techbase.kde.org/Projects/Plasma ... ok#Roadmap
but at the bottom one can read: This page was last modified on 4 January 2010, at 21:18.

You would need to ask about this on the Plasma Development mailing list. However Plasma Netbook, like all other Plasma workspaces are built on a common framework which is under constant improvement to fix things in both the Desktop and Active.

There's an effort ongoing (not that fast, though) to convert the Search and Launch (SAL) UI of plasma-netbook to QML, in order to ease maintenance and development.

Based on what I remember hearing at Akademy: Recently the Plasma developers have focused mostly on Plasma Active, which has improved a lot recently. And since the different versions of Plasma have a lot of common ground, it should be relatively straightforward to bring the Plasma Active developments back into Desktop and Netbook. This is expected to happen in a not too distant future. So all Plasmas are alive and well, even though at times on of them receives more attention than the others.

Good to know. I reported the following bug a while back (originally January)
https://bugs.kde.org/show_bug.cgi?id=295424
and nothing has changed so far.

Sometimes I wonder if I am the only person using Plasma Netbook wanting to lock my session from time to time...

Lets hope for 4.10(?) or 5.0(?) then