We've used miro.com as a whiteboard and I believe this can be licensed as an app for use with teams.
With any cloud based resource make sure you have the privacy settings set correctly. You don't want to brainstorm your companies next big idea in a forum that is open to the public and gives the game away to your competitors.
I have been giving a lot of thought to job training, particularly where the cloud is concerned. There is a huge amount that we could learn and coupled to that there is the company way of doing things. I don't think it is the best use of peoples time to say "go off and learn stuff". The things you learn might not be the things you need to learn.
I think the best approach, from a company perspective, is to say...
We use product/service Omega. In order to develop your competence relevant to the company in product Omega you need to learn
- Subject A (hyperlink to approved training resource)
- Subject B (hyperlink to approved training resource)
- Subject ZZ9 Plural Z Alpha (hyperlink to approved training resource
Any companies approach to training (and particularly cross skilling staff) needs to be focused, resourced and targeted. No external source is going to have the context of your business and its implementation. For that reason the approved training resource probably needs to be a landing page on something like Confluence with internal guidance and links to other approved resources
I see one of the roles of leadership being to curate such material. Part of a manager's role is to develop their staff, they are your product after all. If I can liken your staff unto a bunch of tools then it is your job to make sure your tools are honed and fit for purpose.