Wordpress.
WordPress › Download
I can't remember if it comes with a default WYSIWYG editor. I think it does.
Easy install, easy to use, large user base. It's the simplest way (once installed) for a non-techie to get his thoughts on the 'net.
If the moderators don't mind:
For search engine success, you need an optimised theme. By co-incidence, I have some here:
TigerTom's Freeware - Files
More info. here:
My Troubles With Wordpress Themes
A default Wordpress install is hopeless for search engine marketing.