Firstly, a quick note about the user experience of mobile browsing and mobile ads: A mobile user tends to surf for a much shorter time than they would on a computer, so they need sites to be simple to navigate and quick to load. Some of the mobile sites the user visits may be running banner ads or text ads.

If the user clicks on an ad, they are taken to the advertiser’s mobile site. The advertiser pays for the click and the publisher gets a percentage of the click price.

Ok, so let us say you launch a mobile site and you want to make some money by running ads. You go to your regular web-based ad network for the ads because they have told you that they can do mobile too. What will happen?

Well you might get some mobile-specific ads, but, and it’s a big but, most of the ads will be web ads that have been shrunk down to fit your mobile site. These shrunk down ads may have originally been 468×60 and will have now been scrunched down to 300×50 or smaller. There are a number of problems with this:

Most shrunk down banner ads will look awful and be unreadable. This will not do your site or your users any favors at all.

It gets worse if the user then clicks the ad, because it will lead to a website, not a mobile site. The user will either have to wait ages for a heavy website to load in on their phone (and will probably hit stop way before it loads in).

Smartphone users may see a miniature version of the website displayed. As with the shrunk down banner, the shrunk down website will usually look ridiculous and probably won’t function properly. Since you sent the user there from your site, they may blame you and not visit your site again.

You would make far more money by running mobile ad campaigns on your mobile sites. Mobile advertisers will get a return from their advertising and will be happy to continue running ads on your site.

The opposite is equally bad as well — advertising a mobile site on a web-based ad network. In this scenario, you may have created some smaller banners specifically for mobile, but by using a web-based ad network, your banners may be shown to users viewing full size websites on a computer. If the user then clicks your mobile banner, they will be taken to a mobile site with mobile optimized content — on their computer. Worse still, the user may get an error saying the mobile page can’t be displayed. Either way, you won’t get anything from the click you have just paid for.

Don’t forget, CTRs and conversion rates tend to be higher on mobile too, if done correctly — so you’re really turning your back on easy money by not working with a mobile-specific ad network.

The message here is simple: whether you are advertising on mobile or running ads on your mobile site, always work with a mobile ad network.

Of course, some webbased ad networks may indeed do mobile too, but check carefully what that actually means.