First appearance of Dwight Schultz as Reginald Barclay, who'd originally been intended to be a one-time character to get sent to a mental hospital over his holodeck addiction.
Holo-Wesley's appearance was based on a famous painting by Thomas Gainsborough called "The Blue Boy". His costume was copied in detail and references to the painter and the painting can be found in the script.
This episode was nominated for an Emmy Award for Outstanding Achievement in Hairstyling for a Series.
During Barclay's counseling session with Troi, he mentions that he "knew about the 'flux capacitor,' and didn't need to hear about it from some damn kid." The flux capacitor was the core component of the DeLorean time machine from Back to the Future (1985) and is mentioned multiple times throughout all of the Star Trek series, except TOS.
This episode makes explicit and implicit references to Geordi La Forge's questionable holographic relationship with Leah Brahms.