It amazes me how companies will have free volunteers help people to use their (often expensive) paid subscription products, and then delete all that info those volunteers wrote up. Don't they want people to use their products?! They're less likely to renew their subscription if they struggle or are unable to use the product for their particular use case.
Unaffiliated forums not ran by the company are better in that the company can't decide to just delete all old posts one day (and while the owner could, certain types of unaffiliated forums are usually a bit easier to clone and republish.) The downside is you don't get assistance from people who work for that company, but often you rarely get that in official forums. The usual reason to use official forums is just that they have significantly more users asking and answering questions than unofficial ones.