If you want to support MDN, donate to OpenWebDocs.org. That supports open web content documentation on MDN for everybody.
Personally, I have the repo locally, so Plus isn't tempting. But if it adds something that is of value to you, giving money to mozilla isn't a waste I don't think. That said, Open Web Docs is a good investment. I think it's even tax deductible, but either way, it can be written off as a business expense.
OpenWebDocs is focused on MDN/CanIUse browser compatability data AND MDN content. Many people who used to work for moz on MDN now work with them. OpenWebDocs.org
Personally, I have the repo locally, so Plus isn't tempting. But if it adds something that is of value to you, giving money to mozilla isn't a waste I don't think. That said, Open Web Docs is a good investment. I think it's even tax deductible, but either way, it can be written off as a business expense.