The RSS enclosure element is used to attach media (such as video) to a news item. The original design of enclosures was to enable downloading media attached to news feeds while the computer wasn’t in use – for example, downloading MP3s while you sleep – so you wouldn’t have to wait.
I have to confess, though, that I was never wild about this idea, at least not for FeedDemon’s purposes. If you read a news item that was just retrieved by your aggregator, you probably want to see the enclosure right then and there rather than wait for it to be downloaded when the computer is idle.
More importantly, much (but admittedly not all) of the Web’s media is designed to be streamed, so rather than download enclosures, why not simply link to the media object and let the system’s default media application take care of it? For example, if a news item has a video enclosure, just link to it and let the media application stream it to you – no wait, and no wasted hard drive space.
So, this is how FeedDemon handles RSS enclosures. If FeedDemon encounters a news item with an enclosure, you’ll see a paper clip (“attachment”) icon in the newspaper. Just click this icon to view the media.