While lazy loading and automated ad injection are fundamentally different concepts, from a publisher standpoint the lines between the two are often blurred in the context of digital advertising. In many cases both technologies could in fact be interchangeable, but there are subtle differences that might be less obvious and lead to misuse. We’re going to look at each one individually and hopefully provide some clarity on where one is more suitable than the other.
Lazy loading
This mechanism has been around for quite some time, not just in digital publishing but in web development as a whole. Lazy loading is pretty straightforward to understand in principle, with most of the complexities around it being rather occasional.
In general, what lazy loading does is to introduce a delayed response from a system, using the recipient’s viewport status as a trigger. To put it simply, it provides the ability to activate and load certain elements of a webpage only when they’re being seen (or about to be) and not before. Plenty of benefits can be found in implementing such a feature, the most significant of all probably being better initial load times for web pages requiring significant processing time.
An important distinction to be made here is that lazy loading can be applied to pretty much any component of a page, even though common practices dictate specific use cases. More often than not some sort of pre-loading will be applied as well, meaning that the element will actually be processed in the browser when it’s just below the viewable area, rather than when it’s already within the viewport. This is usually done to ensure a seamless experience, as there’s always a certain amount of time required to process the request.
In the context of digital advertising, lazy loading is most often utilized to deliver better viewability rates for ad placements. This is actually not what the feature was originally created for, but it does a very good job in delivering results regardless. It does, however, have some limitations, due to the fact that it doesn’t have the ability to change how a page renders. Instead it can only control when each element is processed and when it should be displayed.
Smart View
Smart View is our in-house built technology that falls under the umbrella of automated ad injection scripts. While it does share some similarities with lazy loading, such as taking the user’s viewable area as a trigger to process elements, the differences between the two can be quite substantial.
Just like similar reactive features, Smart View has the ability to create ad inventory dynamically based on user engagement, instead of just delaying a fixed response from the system. Looking at more specific practical implications, the most tangible benefit over lazy loading would be that in case an ad impression isn’t sold, its container wouldn’t be visible at all (i.e. there would be no blanks).
Smart View is also fully managed within the website’s header, which means you can pretty much control what happens on each page without the necessity to tweak individual elements to change their behaviour. It’s also quite streamlined in terms of processing requests and doesn’t typically utilize preloading, which means that triggered placements actually offer close to 100% viewability.
As already mentioned, Smart View has some clear advantages when it comes to keeping a clean UX in the presence of multiple ad placements. It’s not uncommon for impressions not to get sold to any SSP, especially in low-interest GEOs. That can potentially leave a lot of blank spaces on a web page, unless some sort of backfill solution or a house ad is displayed instead, which a lot of publishers prefer not to do. With Smart View, the ad containers don’t exist statically on pages, but are rather created in real time only if there’s an ad to be served, eliminating such design issues.
There’s also another key feature that differentiates Smart View from lazy loading. It has the ability to ‘break out’ of the site’s design limitations and deliver ads in any blank space on a web page (such as further down an empty sidebar for example) without having to create additional backend structures.
Use cases
Picking one solution over the other can be tricky, so we always advise booking a consultation with a technical specialist to identify your needs. In fact, the two can often be used in combination based on individual placement characteristics.
That said, if we just look at front end implications, things are less complicated. As a general rule of thumb, if an ad container is crucial to a page’s design integrity, then lazy loading is the way to go, since it doesn’t really affect rendering. On the other hand, Smart View can be applied wherever the existence of an ad is not central to the page’s layout (e.g. floating or in-content placements etc.).
When implemented correctly, both are able deliver increased viewability and CPM rates, but Smart View typically has the edge over lazy loading when it comes to performance.