AdSense Ad Variations: Link Units And Themed Ad Units

important AdSense variations:
Link units and themed ad units are two variations of AdSense Ads that are meant
to further increase the quality of AdSense Ads that get served on websites. Let’s
take a quick look to see what ‘Link units’ and ‘themed Ad units’ actually are:
Themed Ad Units: As their name suggests, themed ad units are the ad units
that are based on particular themes. These themes could be depicted by colors
or special type of graphics that are representative of the event or occasion
portrayed by the theme. The events and occasions could be things like
Christmas, New Year’s Day, etc. Of course, the themed Ads can only be
displayed if they are available from the advertisers and if you have enabled the
themed Ads on your AdSense account (in ‘Ad Type Preferences’). Also, since the
events vary across different locations, the themed Ads are displayed based on
the location of the website visitor. Besides this minor difference, themed ad units
work in the same way as the normal ad units.
Link Units: Link units are another useful way of advertising through AdSense
program. Though the basic premise remains the same (i.e. targeted advertising),
the way link units operate is slightly different. Link units are meant to provide
even more meaningful advertisements to the website visitors by presenting them
with a list of topics (ad keywords) to choose from. The website visitors are then
presented with only those Ads that are related to the topic selected by them;
hence making their website visit more meaningful. The list of topics presented to
the website visitor is based on the website content. So, the topics are relevant to
the context of website. However, the ‘clicks’ on the topics doesn’t make any
revenue for you; it’s the clicks on the Ads for that topic that earns you revenue. As far as implementing of Link units is concerned, it’s done in the same way as
other AdSense type products -- you copy and paste AdSense code in the html
code of your webpage. Note that you are allowed to implement only one link unit
per web page.