Lots of gtkmm (GTK+ C++ API) applications have popped up recently:

• VMWare Player (closed-source, but gratis). People already love VMWare's ability to emulate complete operating systems inside other operating systems, and to clone them and rollback. Soon (now available as a beta) we'll be able to distribute one of these sessions without charge, like sending someone a PDF to view in their gratis Acrobat Reader, but this time it's like getting a full computer in a window instead of a document. LiveCDs suddenly seem difficult in comparison. The linux version uses gtkmm for its GUI, and I expect to see it everywhere. The developers have already given back considerable time, code, and cleverness to the open-source platform that they use.
• Gobby is a collaborative text editor plus chat thingy. More and more people are mentioning that it's truly useful and works. They seem interested in an ueber-reusable C API for the underlying collaboration protocol.
• Synfig does 2D vector-based animation. It seems to be a serious tool for professionals. It looks impressive and seems to create impressive animations. This is almost, but not quite, as cool as when the Muppet Workshop used gtkmm (I will never stop mentioning that.)
• Gideon Designer seems to be yet another next-generation Glade replacement with some extra cleverness for gtkmm programmers. It looks impressive, but we all know that we don't need one of these in C (glade-3), C# (stetic), python (gazpacho) and gtkmm (Gideon). It's silly. However, I assume people are doing this for themselves for fun, and not seriously losing time that they would spend on more productive things, so don't let me spoil your fun.

I haven't used any of these applications yet. Blogging takes time, you know.

When we add Inkscape and my Glom project (finished some day when I get the time or money), I don't think we need to keep asking the gtkmm developers (mostly me) to also code a killer application to justify gtkmm being available on distros (available everywhere now anyway) so that people can code killer applications. That had annoyed me.

This is not a wave of gtkmmification, nor a sign that C++ makes everyone an order of magnitude more productive, or that we should all start using C++ and shouting at the people who don't want to. It just shows that, with GNOME, you can _really_ use just about whatever programming language you are comfortable with.