I posted an informative reply on this topic at the Sketchup Developer's Google group.
(I guess I'll just Carbon Copy it here.)

@unknownuser said:

Is there any possibility of using Google Sketchup within a website ...?
GoogleGroup Topic: To Run Google sketchup within website

I believe you must export models as Collada(.DAE) files for use on websites.

The website would use Google O3D pluginto VIEW the model.
Visitors would need to download and install the plugin.
Interaction can be done on the model by the website visitors, thru Javascriptprogramming. Such as changing colors, or materials, moving objects around, etc. But all these things I think must be drawn in Sketchup.

There is no basic editing / modeling capability in O3D. Only manipulation of components.

O3D Technical Overview
http://code.google.com/apis/o3d/docs/techoverview.html

O3D Developer's Guide
http://code.google.com/apis/o3d/docs/devguideintro.html

Working Webpage Examples:

Smart Designer by SmartFurniture.com
http://www.smartfurniture.com/smartdesigner
Smart Designer® is a new online application that enables consumers and businesses to design and order their own furniture products. They can then interact with those customized products in the context of a 3D space that simulates their homes or offices.

Home Configurator (Firefox only)
http://o3d.googlecode.com/svn/trunk/samples/home-configurators/homedesigner.html

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