I'm building a webapp that depends on oauth with an outside provider. Before I send the user to the oauth page I'd like to explain to them why I need the permissions I do. Obviously I cannot do this on the oauth page since it's owned by a 3rd party. So I'd like to explain somehow before the user is redirected to the oauth page.
A couple ideas I had were:
- popup a new window before redirecting that shows an image of what they should expect and explains everything. this could be annoying (ugh popups) and won't work well on mobile
- requiring 2 clicks - the first "login" button wouldn't actually redirect to the oauth page but rather shows some sort of instructions and contain another login button that actually does the redirect. this is also kind of annoying though since it's an extra step.
Can someone point me to a site that does this well already?