Canon is official story material disseminated by any of the Glyos toyline companies or creators in charge of those companies. There are two types of canon: "Hard" and "Soft". Both are equally real and valid but Soft Canon is harder to source and record.
"Hard" Canon is found on blog posts and official social media accounts. It's easy to copy and source and there are also back-ups in the form of the WayBackMachine or other sites. This information is hard to lose barring a massive collapse of the internet.
"Soft" Canon is found on forums and blog comments or communicated by word of mouth. Forums can be completely shut down with no trace (as happened with the October Toys Forum) and an entire blog's comments can be deleted by an errant click or bad software update. Word-of-mouth is difficult to parse because it depends on the creator not misspeaking, the listener not misunderstanding, and then the listener not misremembering or misinterpreting the information.