Liferea is not, at least when a feed shows only a few lines and links
to the true article, and so other popular readers. AFAIK Straw was the
only one truly offline reader but it's broken (in sid). Even google
reader + gears can't fetch articles linked from a feed like that:
http://osnews.com/story/22145/Linux_2_6_31_Released which has only a
small part/abstract of the article. In such case you have to be online
to read the full article even when all feeds are synced/refreshed.
Am I missing something or there is no such software?