Tips for Generating Good Feeds

RSS and Atom are easy to work with, but like any new format, you may encounter some problems in using them. This section attempts to address the most common issues that arise when generating a feed.

    Distinct Entries — Make sure that aggregators can tell your entries apart, by using different identifiers in rdf:about (RSS 1.0), guid (RSS 2.0) and id (Atom). This will save a lot of headaches down the road.
    Meaningful Metadata — Try to make the metadata useful on its own; for example, if you only include a short <title>, people may not know what the link is about. By the same token, if you shove an entire article into <description>, it’ll crowd people’s view of the feed, and they’re less likely to stay interested in what you have to say. Generally, you want to put enough into the feed to help someone decide whether they should follow the link.
    Encoding HTML — Although it’s tempting, refrain from including HTML markup (like <a href="...">, <b> or <p>) in your RSS feed; because you don’t know how it will be presented, doing so can prevent your feed from being displayed correctly. If you need to include a a tag in the text of the feed (e.g., the title of an entry is “Ode to
    XML Entities — Remember that XML doesn’t predefine entities like HTML does; therefore, you won’t have &nbsp; &copy; and other common entities available. You can define them in the XML, or alternatively just use an character encoding that makes what you need available.
    Character Encoding — Some software generates feeds using Windows character sets, and sometimes mislabels them. The safest thing to do is to encode your feed as UTF-8 and check it by parsing it with an XML parser.
    Communicating with Viewers — Don’t use entries in your feed to communicate to your users; for example, some feeds have been known to use the <description> to dictate copyright terms. Use the appropriate element or module.
    Communicating with Machines — Likewise, use the appropriate HTTP status codes if your feed has relocated (usually, 301 Moved Permanently) or is no longer available (410 Gone or 404 Not Found).
    Making your Feed Cache-Friendly — Successful feeds see a fair amount of traffic because clients poll them often to see if they’ve changed. To support the load, Web Caching can help; see the caching tutorial.
    Validate — use the Feed Validator to catch any problems in your feed; it works with RSS and Atom. Also, don’t just run it once; make sure you regularly check your feed, so that you can catch transient errors.

source: https://www.mnot.net/rss/tutorial/#which-format-should-i-choose