It makes claims of zeroing out the local storage, but does not seem to do anything with regard to erasing your social media footprint. I would like your recommendation on scripts which comprehensively delete posts/history on Reddit, Twitter et al. and make them unrecoverable.
edit: I just noticed a post by @randomuser87178 which probably answers my query
Just an FYI, Shreddit is not particularly effective for deleting old Reddit post and commenting history. There is at least one service (Pushshift [1]) which sits at Reddit's API endpoint and hoovers up every single comment and post as they are made in near-real time. These are then archived in the Pushshift database, which is accessible by unauthenticated public API as well as through monthly post and comment JSON dumps.
There are several third-party search engines which use the Pushshift API underneath, most prominently Camas Reddit Search [2]. Ironically, it is way faster and more thorough than Reddit's actual search feature. You can do a full-text search of a specific user's history and filter by subreddit, score, and post date in a couple of seconds.
Since Pushshift contains comments and posts in the state they were made when they were originally posted, editing or deleting them from Reddit proper, or deleting your Reddit account, does nothing to prevent them from being searchable in Pushshift.
Pushshift does support opt-outs, but they have historically been slow to process them. Apparently a new opt-out system will be in place as of this weekend [3].
That said, Pushshift isn't the only Reddit archiving game in town, just the most visible, so even if you opt-out of Pushshift your post history is still probably in somebody else's archive. Also, I'm pretty sure the opt-out just removes your posts from the public API, I think the historical dumps still have your data in them if somebody were motivated enough to download all 80+ TB of them.
Your best bet for preserving privacy on Reddit is to (1) never post identifying details, (2) change accounts periodically, and (3) keep a few alts for commenting on different subreddits, especially if posting on subreddits that somebody can infer identifying details from (eg: the subreddit for your city).
You are very correct, this just makes it harder for someone who isn't too motivated to find all your posts. Anything you post online should be considered permanent anyway (unless you actually want to find it later, I guess).
That's why I use a utility called Shreddit and some custom scripts to delete all my reddit/Twitter/whatever posts except the latest N.