Watching it back ten years out of release, some of the things that stick out might appear trivial, but it's the details that really last. So when Tony makes a joke about MySpace, it sticks out like a sore thumb. In 2008, MySpace was invincible (they turned over $800 million in revenue that year), but it was only a couple of years away from the bubble bursting, which dates the joke and the movie horribly in hindsight.
And worse, much like the Wii that's proudly displayed in Tony's apartment as some sort of status symbol, it makes the "cutting edge" genius look like a dinosaur that doesn't realise it's about to be extinct.
At least the more modern dating mistakes - like Black Panther's "what are those?!" moment and Jessica Jones' mention of the ice bucket challenge - aren't entirely unprecedented, then.