If you have a website that for some odd reason doesn't provide an RSS feed, several 3rd party services will make one for you. Such as:

Feed Creator You have to have a bit of HTML knowledge for this one.

Feed43 is a freemium service with free and reasonably-priced annual plans

Feedity doesn't have a free plan, but claims to have an API for developers

Cloudflipper is a free service that converts your SoundCloud dashboard into an RSS feed.

TwitRSS is a free service that converts your Twitter stream into an RSS feed.

There's also a Google Script that also converts your Twitter stream into RSS.

If you can self-host PHP scripts (which is almost everybody) you can get RSS-Bridge and covert any number of social media streams into RSS feeds.