13 Jun 06
18 Jan 07 9:38 pm
I haven't tested with layers, but I'm assuming that you won't need to do anything special.
The problem with tables is that the way it's written in the HTML is in a different order to how you actually want a reader (and a search engine spider) to read the page. Even though the column on the left isn't the main part of the page, (and even though the ads might appear way down the bottom of the column) the search engines see this column first, so put the good ads there.
I guess with divs, layers and CSS positioning you just need to make sure that your most prominent adsense block appears earliest in the source code. I don't think the spiders pay much attention to CSS.
Download and use the Google Adsense Preview Tool to figure out which ads are bidding the highest (the ones at the top of the list) and then see where they appear on your page. (Note that they won't always be the same ads, but *some* will be the same, so you should be able to work it out.)
Let me know how you get on!