Can I contribute exclusively to Adobe Stock? Is there a special requirement to do so? Is there an advantage if I do so?
Adobe do not ask for, or take, exclusivity. You can choose to offer photos to Adobe only, but they will not register this, nor pay differently.
If you list the same assets on multiple Stock sites, you risk dilution. Why would Adobe customers pay for an asset they can get elsewhere and vice versa?
It all depends on what works best for you.
If you list the same assets on multiple Stock sites, you risk dilution.
By @Nancy OShea
My Shutterstock bestsellers are Adobe stock slow sellers and vice versa. But yes, I agree, you should do a stringent selection of stock providers you want to contribute to. And, if I may say so, Adobe stock is the provider who distributes the most percentage to me as a contributor.