https://developer.twitter.com/en/developer-terms/more-on-restricted-use-cases
And, more generally:
https://developer.twitter.com/en/developer-terms/agreement-and-policy
https://www.reddit.com/wiki/api-terms
« d. User Content. Reddit user photos, text and videos (« User Content ») are owned by the users and not by Reddit. Subject to the terms and conditions of these Terms, Reddit grants You a non-exclusive, non-transferable, non-sublicensable, and revocable license to copy and display the User Content using the Reddit API through your application, website, or service to end users. You may not modify the User Content except to format it for such display. You will comply with any requirements or restrictions imposed on usage of User Content by their respective owners, which may include « all rights reserved » notices, Creative Commons licenses or other terms and conditions that may be agreed upon between you and the owners. »
et ici :
https://www.redditinc.com/policies/user-agreement#text-content6
« When accessing or using our Services, you will not… Use the Services to harvest, collect, gather or assemble information or data regarding the Services or users of the Services except as permitted in these Terms or in a separate agreement with Reddit; »
