In regard to CMS interfaces I would say we could split them in 2 main branches [*1]:
the ones with a control panel, where you go and usually see a list of pages (blog articles/ecommerce products), then you can update/modify each page, by filling form fields. More like: WordPress, Joomla...
the ones where you look at the page, you click on the section you want to change and it appears a small editor where you do the changes. More like: Jimdo, Google sites (i think, not sure of this one), Many others.
Besides the pros and cons of both approaches [*2]: in some way I think the ones based on control panels (forms to fill) seem to work better when you have many contents to manage, like big blogs, big eccomerce sites, while the other approach (click and change) seems better for small websites.
But at the end of the day, which one is easier to understand/use/interact for the non-tech-geek final user? (I.e. my mother)
UPDATE: are there any researches/tests about this subject?
[*1] I know there are platforms that try to give you both approaches, example in WordPress after you logged in you see directly in pages small icons to modify the page, but I still think WP's control panel is more a form based interface, I mean if I have to change an article in my blog I use the control panel filling the forms.
[*2] feel free in your answer to explain what other pros and cons you see