Poking is kind of like an open application, while applying to a listing shows an extra interest in a vacant role in the company. What are pokes
There is not much difference to applying and poking for existing users on WA.works. Both grants access to the WA profile. But when you apply to a listing, you can add an application text. Because it's so easy to hit that poke button, most existing users choose to poke to get in touch with interesting companies.
Listings are more used in the company's own channels and as a screening tool.