- Custom feed redirection.
- Custom Domain redirection.
- Classic vs New feed URL, and Blogger vs BlogSpot / domain served feed.
- Feeds served by third party servers (FTP publishing).
- Feeds from private blogs (which don't exist).
- Cached feed content.
Custom Feed Redirection
A custom, redirected feed, redirected through FeedBurner or a similar service, will be affected by problems with the service. When you check out a problem with a redirected feed, it may be helpful to compare the redirected feed content with the non redirected feed content.
Custom Domain Redirection
A feed coming from a blog that's published to a custom domain will be affected by the custom domain DNS issues. Feeds redirected through DNS addresses that use spurious solutions, like frames or URL forwarding, will be slow to, or never, update.
When you check out a problem with a feed from a blog published to a custom domain, start by examining the DNS setup for the domain. For each person reporting a problem, see if they are using the BlogSpot URL, or the domain URL. If the former, check the BlogSpot to domain redirection.
Feed Format and Source
For any feed with a problem reported, find out if the problem is with a classic, or a new, feed URL. The exact feed URL may be relevant. Look at the 3 feeds served from this blog page, as provided in the blog header.
Here, we have 2 new URL feeds served from the custom domain, plus one feed served from Blogger.com.
<link rel="alternate" type="application/atom+xml" title="The Real Blogger Status - Atom" href="http://blogging.nitecruzr.net/feeds/posts/default" />
<link rel="alternate" type="application/rss+xml" title="The Real Blogger Status - RSS" href="http://blogging.nitecruzr.net/feeds/posts/default?alt=rss" />
<link rel="service.post" type="application/atom+xml" title="The Real Blogger Status - Atom" href="http://www.blogger.com/feeds/24069595/posts/default" />
Third Party (FTP Published) Feeds
When you're looking at feed URLs, watch out for a feed that comes from an external third party server. Feeds published from non Google servers may have many issues. Use of the Blogger based feed, vs the third party server served feed, may be especially significant. We've even recommended use of the Blogger served feed, as a workaround for feed problems in some FTP published blogs.
Feeds From Private Blogs
A feed coming from a private blog will never be updated. If the blog was just made private, you'll be seeing the blog feed as it was before the blog was made private, for a long time.
Effects Of Caching Upon Your Clients
Also, consider the effects of cache. Your readers that are affected by a local cache, or an upstream cache, will see irregular performance when they view a feed. Depending upon the nature of a blog, a given blog may have more readers who use a bloglist or feed reader, and who have Internet service that includes an upstream cache. A regional, or reader service, affinity may point to a cache issue.
Summary - When Reporting A Problem
Anybody reporting a problem with a feed viewed in somebody else's blog should state their geographical location, ISP name, and type of Internet service. Anybody subscribed to a feed with a problem should state the complete and precise URL of the feed. All of these details may be relevant to the problem.
All of these are details which will affect peoples access to any blog feed, and the displayed content in the bloglists and feed readers which they view.