I read that Reddit is a news aggregator; if that’s the case, does it support RSS feeds and can I add my own?
Reddit generates a RSS feed for every subreddit.
For r/aww the feed is available at https://www.reddit.com/r/aww/.rss
You can also combine feeds: https://www.reddit.com/r/aww+firefox/.rss
Inline-reddit.com offers better image feeds for Reddit. For r/aww the URL is http://inline-reddit.com/feed/?subreddit=aww
Or you can sort by hot, new, controversial: