Opinions on syndication feeds

If you're unaware of what a syndication feed is, it's any file on any website following a specific file format, listing recent updates/entries/items/posts/etc. Syndication feeds can be read with feed reader software. The two main syndication feed formats are RSS 2.0 and AtomEnabled, both XML-based.

The good

Syndication feeds are a great way to be notified of new information! One doesn't have to check multiple websites for updates; one just has to check one's feed reader.

The bad

I think many feed readers in existence are farcical. There is no reason for a feed reader to require one signs up for an account, and also no reason for it to limit the number of feeds depending on how much one pays. If a feed reader does either of those things, I consider it a scam.
The only functionality a feed reader actually needs to have is to make HTTP requests and parse XML, which can be done entirely locally. The only time "cloud storage" would be relevant to a feed reader is if one wanted to synchronize one's feeds between multiple devices, but mandating it is just silly.
Fortunately there do exist feed readers that work in a sensible manner.

The pedantic

The names involved in syndication feed formats are a mess:
Syndication feeds are often called "RSS feeds" regardless of whether they're in the RSS format. Similarly with feed readers being called "RSS readers" even though most support both RSS 2.0 and AtomEnabled.
The icon for the RSS format is often used for AtomEnabled feeds, even though AtomEnabled has its own, separate, icon.
"RSS" isn't really short for anything. It was once short for "RDF Site Summary", which was only accurate for four months in 1999.

RSS 2.0 is kind of a messy format. The content of an entry is HTML as a plaintext XML node; i.e. it is either double-entity-encoded or placed in a CDATA section. It has also been documented how RSS 2.0 is one of many slightly different incompatible "RSS" formats. AtomEnabled does improve on RSS and avoids these sorts of hairballs, but the two are about equally common. It probably doesn't help that the naming shenanigans might make a developer who's unaware of the differences default to RSS 2.0.