I have a job site and I use Leaderboard (728 x 90) with Large Arial font. As I know an Arial Large font ad slot should look like below: However all my ads are shown with medium font size even though I have selected Large font size as follows: I just want to see Large font and don't know why large font is not shown in my ads. Has this got anything to do with the font size used in the text of the site? Any advice to resolve this matter highly appreciated. Thanks in advance!
My advice would be to use a font that is similar to your content so it doesn't look out of place too much
You have got the option of small medium or large, and and also Aerial, Verdana and Times. These are probably the most common fonts that people use so you can easily choose the font that matches your content. The worst thing you can do is try and make it really big so it stands out, that's not what it's all about when it comes to Google AdSense.
Google AdSense is an ongoing project, it could take you a year, two years, even more to get it right.
I am noticing a similar problem on my site. I choose Verdana 'small' but they always show large fonts instead for my 300x250 ad units which does not match my content font-size. I almost think they are doing it on purpose.
I think the decision weather to use large or small fonts should be done after testing with both. In my case I have higher CTR when I put large font.