Hovertext, or alt text is the text that shows up when hovering over an image on a page. Willis often uses this to give a random piece of information or provide an alternate punchline.
The first instance of hovertext appeared on the Dumbing of Age strip dated February 14, 2013. Appropriately, the text ran "what i can add HOVERTEXT???"  From that day forward, hovertext ran on Shortpacked! through to the end of its regular updates (and onward) and has ran on DoA ever since. Hovertext has not run on the Roomies!/It's Walky! updated rerun site, or on It's Pregnancy! due to its being hosted on Tumblr.
Hovertext initially was not view-able to readers using mobile devices until the DoA mobile website was updated with a fix. Mobile users should therefore touch the blank space below every comic to get the hovertext.
- ↑ "Scoot", February 14, 2013. http://www.dumbingofage.com/2013/comic/book-3/02-guess-whos-coming-to-galassos/scoot/.