If no updates are appearing, it is also possible that the feed itself is not updating, even if it contains valid RSS and even if the site that it is syndicating from is updating.
I don't understand this sentence. What is the "site that it is syndicating from"? Is that LJ, or is it the site providing the RSS file? The "feed itself", is that LJ's side of things or the RSS file on the other server? I'm really confused.