This is old news related to the first incarnation of Gnome-vim, which was implemented by wrapping a Zvt Widget as a bonobo component, and running a text-mode Vim inside the terminal. It worked, but had limitations...
June 17, 2002: I've done some playing around with gnome-vim using Vim's client-server features in the last few months, but decided that this isn't a long-term solution for gnome-vim. I'd like to instead put the bonobo-server code in vim itself, and I've done some investigation and planning in this direction. This would make gnome-vim more stable, less of a hack, and would allow (for example) vim toolbar buttons and menu items to appear in the embedding program's window. As I currently don't have much free time to work on this, I could probably use the help of a good C programmer, especially if he/she is familiar with Bonobo.
April 2, 2002: Yes, there's a problem with the newer versions of Evolution (I think since 1.0.2), because they cause the editor to save every few minutes, which causes vim to jump into command mode. I'm working on an new version which uses the client-server functionality in vim 6.x, so that it can save files without interrupting the edit session. Please check back in a few weeks.
April 2, 2002: I submitted a patch to Evolution a few weeks ago which will allow the user to select an editor component in the mail settings. I'm hoping that it'll get merged in before the 1.2 release. The patch is available here, if you're interested.
December 4, 2001: Some people reported problems with the focus. I made a change and you can focus on vim by clicking in the window now. Get version 0.1.3.
December 2, 2001: Fixed a mistake in GNOME_VIM.oaf which prevented gnome-vim from working at all. Thanks to Alexander Wagner for helping me track this down. Sorry for all the bugs.
November 30, 2001: In record-breaking speed (about 10 minutes), a new release has be created which includes the modify-evolution-mail script which I forgot to add in the initial release.
November 30, 2001: Initial release.