I've been reading up on various conflicting posts and articles online that refer to SEO and the use of IFrames and AJAX random content boxes.

Does anyone have any experience of search engines spidering this type of content?

I'd like to use the rotating day-of-the-week type content so the site is 'updated' or appears to be more than it actually is.

I've heard there are tags you can use to help with IFrames etc but I'm really confused about the whole thing.