Storytelling is often used support communication in early User Experience (UX) design, and the resulting stories are frequently visualized in the form of storyboards. However, storyboarding, the creation of storyboards, has also been identified as an important obstacle to the adoption of storytelling in UX design. Most UX designers do indeed not possess the drawing skills needed to produce professionally-looking storyboards. A problem that can be potentially overcome (or at least ameliorated) by using alternative (digital) storyboarding tools. A study into the user acceptance of existing tools is introduced in this paper. The results show that while traditional tools like pen and paper are still very much valued, digital tools are getting increasingly popular. We identify important limitations of existing tools and formulate requirements for future storyboarding tools.