Mark Coker, CEO of Smashwords, announced this past weekend that he'd taken steps to make the website more child friendly. First time visitors will now encounter a filter that hides the adult content from view.
Don't worry; it's easy to turn off. The toggle switch is clearly visible in the browser window.
The new filter was inspired by Google's "Moderate Safe Search" option, and it replaces the old Prude Filter (I didn't know they had one). The old filter was less selective and it also wasn't the default setting.