It’s important to understand the difference between your display URL and your destination URL in your pay per click ads. Your display URL is the URL that searchers see when they encounter your add. Usually, the best URL to use for your display URL is your index page or website home page. But that isn’t a requirement. You might use a subdomain URL or a particular URL if you so choose, but if you have a long URL with a long string of special characters, I wouldn’t use that for a display URL. Google AdWords limits your display URL to only 35 characters so you are a bit limited in what you can use anyway. Other search engines have similar policies.
Your destination URL can be longer and you can use special tracking codes or special characters in that URL. For instance, if your landing page is a page within your website and you have a tracking code then you can make that your destination URL while your home page is your display URL.
There are some limitations to the display URL-destination URL combination. They have to be on the same website, for one thing. In other words, your display URL can’t be at www.mydomain.com and your destination URL at www.thisdomaininstead. You can’t use redirects and bridges either. No cloaking. Those are considered blackhat techniques and could get you banned from the pay per click search engines.
When it comes to the combination of display URL and destination URL, you want the visitors to your landing page to trust you so don’t give them any reason not to.
