I don't like it. It solves one problem but introduces a whole lot more.
Basically...
- Just as a hover is not a click; scrolling to the end of the viewport does not indicated intent to load more content, it just means the user has scrolled to the end of the viewport.
- Most implementations do not adequately cope with any interaction other than the scroll wheel of a desktop mouse. eg. I use a wacom tablet and drag the scrollbar a lot, and most implementations jump to the wrong place when I release the button (pulling down causes more content to load, releasing causes the page to jump trying to resolve the new scroll position).
- Most implementations do not adequately handle URLs/pushstate, so if you are several 'pages' into the content and refresh/reload you have to scroll and wait, scroll and wait...
- Many implementations don't do a great job of detecting when the user has reached the end, requiring the user to sort of 'bang the window' at the bottom trying to induce the load.
- Astoundingly you still get sites that implement both infinite scroll and a footer with links you need to use. Which is just messing with people.
...the list goes on. Basically I understand the appeal, but the problems far outweigh the benefits. If really pushed, why not give people a "load more" button and an "enable infinite scroll" checkbox? Let the user choose.