Blondie Watch
Before she married Dagwood Bumstead, Blondie’s name was Blondie Boopadoop. That’s what Wikipedia says, that’s what King Features Syndicate says, that’s what the Library of Congress says. But… was it? Out of curiosity, I looked into it, and while “Boopadoop” had been used in official promotional material dating back to 1930, I have yet to find it used in an actual comic strip. A few caveats: my search was by no means exhaustive (it would be nice to have the collection IDW put out) the OCR might have missed something, or maybe there are some gaps in the archive. I would assume “Boopadoop” came from creator Chic Young, or at least had his approval, but it’s odd that he apparently never put it into the strip, so while it’s offical enough, it’s not 100% Comic Strip Canon. Not that the strip was necessarily super-strict about continuity, mind you, just ask the Woodleys’ missing children.
Below are some of my findings; it’s interesting that some of the comic strip’s storylines would also play out in the letters section.

Belleville Daily News Democrat, August 18, 1930
Santa Fe New Mexican, August 23, 1930
Lebanon Daily News, October 8, 1930
The Windsor Star, March 12, 1932
Tampa Bay Times, December 20, 1942