On the TV Tropes page for Commonality Connection (Warning: TVTropes link!), the page image is the following:
It shows Dave Davenport, of Narbonic fame, speaking with a girl named Jamie as they come to the realization that they both hold jobs as henchmen. On that TVTropes page, this is simply linked to the Narbonic page, but I don't recognize the panel and my attempts to reverse-image-search or search relevant text isn't helping me much.
Was this one of the paper book bonus story-lines? A dropped story-line? a fan-creation? The font doesn't look quite right for Shaenon's style (too regular, like it's typed in), it's in color which generally only happened for Sunday strips, and the drawing looks too polished for the "drawn on lined notebook paper" style of most of the dropped storyline sketches.
I have a vague memory of, in my last archive trawl of the Director's Cut version, seeing Shaenon mention a planned storyline for Dave finding romance outside of the office before she realized that the Dave-Helen-Lovelace dynamic was enough, but I can't find that reference now.