Reddit (https://www.reddit.com/) is an established site with tons of online communities, known as subreddits, for generic as well as specialized and niche topics. Among others it's used by artists for social networking, interviews, sharing their creations, etc.

There are already plenty of Reddit URLs in the database as such it makes sense to clean up Reddit URLs by removing tracking parameters, rejecting search queries, and normalizing the URL format.

User URL paths s can also be shortened as /u/<username> which will redirect to /user/<username>

URLs considered for rejection:

* Reject for online community and social networking

URL slugs can apparently be safely omitted:

http://www.reddit.com/r/Music/comments/1nzjqm/im_daniel_lopatin_pka_oneohtrix_point_never_ama/ 
-> http://www.reddit.com/r/Music/comments/1nzjqm/

via https://musicbrainz.org/relationship/1f171391-1f98-4f45-b191-038ec3b12395 (STYLE-260)

URL to OP can be further shortened:

https://www.reddit.com/1nzjqm/

URLs can have various parameters appended that seem to serve no use for the user:

https://www.reddit.com/r/beta/comments/7wj0lj/what_is_with_the_st_and_sh_bullshit_that_the_ios/

E.g.

• sh
• st
• utm_source
• utm_medium
• context (affects comments display)

Last but not least, there is https://old.reddit.com/ which will render the old site design. This should also be normalized to https://www.reddit.com/
The old design can also still be enabled in user settings.

Reddit API documentation:
https://www.reddit.com/dev/api/