[shingen]

Both, ads that make money while asking for money.

This plea brought to you by Encyclopedia Britannica, please support Wikipedia with a donation.

[babebridou]

This would actually be one of the better ways to do it. The link would only lead to Wikipedia donations, and the business would be essentially paying for public goodwill, a hefty sum of it.

Just imagine Coca Cola making a big donation to Wikipedia just to have its name figure on the donation ad for the "Soda" category. I'm not sure how the community would react to this, though.