You're scrolling through your Facebook feed on your phone, and you see an article worth reading. You click the link, but instead of the article you were expecting, a giant full-screen ad prompts you to download the news site's app.

Annoyed, you leave the page. Web. Experience. Ruined.

Those ads are called "interstitials," and they are overly common and widely hated. So why are they still used in Web design and online marketing?

The answer is pretty simple. Interstitials are like billboards on the highway: They put your message in a place where people will be forced to look. But billboards do not actively interrupt the experience of driving, so they're not annoying. Interstitials, on the other hand, bring Web browsing to a dead stop.

Here's the case against interstitials

In 2014, Google felt that interstitials created a poor user experience. Before making the decision to remove them, the company wanted hard data and analyzed its use of interstitials to promote the Google+ mobile app.

Its case study found that interstitials increased bounce rates and had little to no impact on app downloads. Faced with an interstitial ad, 69% of visitors abandoned the page and did not go to the app store or continue to the mobile website.

Google then ran a second experiment to see how removing the interstitial would affect product usage. This time, it promoted the app in a less intrusive way with a smart app banner. After removing the interstitial, one-day active users on the mobile website increased by 17%.

Google decided that these results warranted getting rid of its own interstitial app ad, and that interstitials should be a negative ranking factor in its mobile search algorithm.

Say goodbye to interstitials

As of November 2, "pages with app install interstitial that hides a significant amount of content on the transition from the search results page won't be considered mobile-friendly."

Google is just like any other business out there: It wants to give their customers (users) the best experience with its product (Google as a search engine). 

By cutting ties with interstitial ads, Google can create a cleaner user experience, and in all fairness, the company has made it pretty clear that these ads in general are not a best-practice.

So what does this mean for you?

It's time to kill any full-screen interstitial ads you may be running. They create a terrible user experience and are more than likely shooting the overall bounce rate of your website sky high. Moreover, as the study by Google shows, that's not a spitball remark. Google wants to make sure that the customer comes first, and it has started to hold website owners to that same standard (which is a good thing).

If you want your site to actually do a good job of converting mobile visitors into real-world customers, forgo the interstitial. And if you have one running that promotes an app install, your Google rankings is now suffering because of it.

Consider the notification bar

Instead of bombarding visitors with a full-screen ad, consider conveying your message in a smaller, less obtrusive format.

Adding a notification bar can promote a product or service on your mobile site without destroying user experience. A notification bar allows you to display a short marketing message above the header on your site or even at the bottom of the page, depending on your display preference. The user is guaranteed to see the message, but the mini ad won't interrupt their experience.

A notification bar may seem like it doesn't have the same attention-grabbing power as an interstitial, but when used properly, it can make a huge impact on your conversion rate.

For example, The Gladly, a restaurant based in Phoenix, Arizona, added a notification bar to its site in September 2014 to promote its participation in restaurant week, increasing its online reservations by 70%.

The company also ran another promotion earlier that year and estimated that the notification bar accounted for a minimum of $9,000 in extra revenue for it that month.

Talk about a positive effect!

Although using a smaller ad seems counterintuitive, doing so creates a better experience for website visitors.

Effective Web design and mobile advertising centers on the user—not your product. Banish interstitials, and watch your traffic and downloads grow.