This places a small text link on the ad blocks on your site - it's similar in size and appearance to the "Ads by Goooooogle" link that has always been there.
Advertisers can click on the new link to find out about advertising on your site.
Any advertiser who clicks on the link will be transported to the Google AdWords "Onsite Advertiser Sign-up page" - also known as the "landing page", where they are given details about Google AdWords in general and advertising on your site in particular.
It's possible for you to customise the landing page associated with your site - to a certain extent.
You can upload a logo, change the colour scheme of the page, the text and the links to match that of your main site.
You can also edit the text message that the potential advertiser sees - possibly explaining a little about your site, the sort of areas it covers - at the moment and in future, who your target audience is, whether or not you have a newsletter etc.
If you really want to, you can even turn the option to have the "Advertise on this site" link displayed off.
Here's how to modify your landing page from your AdSense account:
- Click on the "My Account" tab, click the "Account Settings" tab.
- Scroll down to the "Onsite Advertiser Sign-up" section at the very bottom and click "edit".
- The "subscription" is set to include the "advertise On This Site" linkby default.
If you want to turn it off then just uncheck this box.
- If you are leaving the link on then you can now upload a logo for your site - max size 100 X 100 pixels, in JPG, GIF or PNG formats only.
- Decide whether you want to retain the default description or create your own custom text to highlight the main features that you think advertisers should know about your site(s).
- Choose the colour scheme for your landing page.
Use the "Preview page" button to check how your new landing page looks.
- When you're happy click on "Save changes".
Possibly Google will introduce "channels" for your landing page in future.
This feature is very new and only time will tell how best to use it.
However, previous results from AdSense have shown that webmasters who take a little time to customise AdSense code for their websites tend to do (much) better than those who just use the default settings.
So it seems likely that some degree of customisation is desirable.