This is important for some sites as the information might be in an academic or professional journal that requires payment, either per paper or a subscription to access it.
I am very much against this as I think it goes against the Stack Exchange philosophy of improving the internet with free information. I also feel that hitting a paywall is the same as link rot as the information is not readily available to the user who is looking for it to verify or just learn more about the information.
I was wondering what others feel about this and if there is any sort of policy for Stack Exchange as a whole on links to a paywall site or is it handled on a site per site basis?
This question is not in relation to linking to a paid site that the poster either controls or has created content on but to a site used by the academic and professional community that charges an access fee. I think that is different then trying to direct someone to content you made in order to profit.