Some dude asked how he could avoid pooping for three days for undisclosed reasons. It took off from there and birthed the Fediverse's first real original meme/copypasta. The equivalent of "Narwhal bacons at midnight" on Reddit.
Every 3 days is the upper range of normal, what's more important is if you went from 3x/day to once every 3 days or something you should probably see a doc then
It can be perfectly normal or it can sometimes not be if it's not your normal habit. Everyone is different. If you don't poo every day and you feel fine then it's nothing to worry about. If you normally poo every day and then don't and you feel sick then you probably just need to try a better diet to help you go. Everyone has a slightly different poo schedule and that's totally fine.