It's not exactly new, but you probably encountered far more sites with infinite scrolling functionality in 2012 than you did in 2011, and there's a good chance you'll come across even more in 2013.
With popular services like Twitter and Pinterest bringing infinite scrolling into the mainstream, it's no surprise that more and more designers and publishers are considering doing away with old school pagination.
But is infinite scrolling a good trend or will it soon become a design worst practice?
Infinite scrolling: the pros
Fans of infinite scrolling believe that it can provide for a better user experience. Reasons for this include:
Clicking from page-to-page through a paginated experience is typically a time-consuming process that, while pragmatic, rarely seems like an efficient or satisfying way to browse content. The infinite scrolling experience, on the other hand, can be incredibly efficient and, when implemented well, provides for a more enjoyable experience.
Made for touch
Infinite scrolling has become more popular as smart phone and tablet ownership has surged, and the infinite scrolling experience is one that can be found in numerous mobile apps. With our increasingly touch-centric world influencing interfaces, it's only natural that something like this would find its way into the general web design toolkit.
Potentially greater content exposure
Pagination often discourages users from perusing large volumes of content. Google is one of the best examples of this: most of us rarely go beyond the first or second page of Google search results. Infinite scrolling, however, changes the game and in some cases, results in the user seeing more content than she would have in a paginated experience.
Infinite scrolling: the cons
Infinite scrolling isn't without its drawbacks, however.
Infinite scrolling often introduces numerous navigation issues. Although bookmarking a paginated search results page is inherently a risky proposition for users, the option to do so is basically taken off the table altogether with infinite scrolling.
Far more worrisome: navigating back to an infinite scrolling page is typically a nightmare (most of the time the user must start from scratch) and because many infinite scrolling implementations fail to indicate to the user just how much content there is, the overall experience can be as disorienting as it is smooth.
One of the biggest questions asked about infinite scrolling has to do with SEO. Google is capable of indexing content rendered through AJAX, and infinite scrolling implemented as a progressive enhancement should alleviate SEO concerns, but if you overlook these details, it could spell SEO trouble.
So is infinite scrolling the best thing since sliced bread, or the worst thing since Flash? That depends. While the successful use of this functionality on high-profile services like Twitter and Pinterest suggests that the infinite scrolling trend will continue, it's important to recognize that it hasn't worked everywhere.
See below for Etsy engineer Dan McKinley's slides on “Design for Continuous Experimentation”...
At the end of the day, any design trend considered worth exploring should be explored in the context of a website's purpose, and the needs, desires and expectations of its users.