It was Robert van Poelgeest who pointed me in this direction. He mentioned the feature of enclosure elements in RSS feeds.
The element is a child element of in an RSS feed and is used for enclosing a related file accompanying the blog entry. An enclosure-aware aggregator is able to use this URL endpoint to start a download of the file. This should happen in a asynchronous fashion. Whilst the blog entry is already readable, the file will be downloaded in the background. More on a usage scenario can be read here.
Although this can be used for good, it also allows the no-click wait distribution of ads, maybe even viruses. There’s already a company that specializes in ads through RSS feeds (through this Dutch news flash). I think this can also be done as some sort of footer in each RSS , but the offers more possibilities. Dennis van der Stelt also mentioned ads through RSS in his comment in this post on virtual marketing.
It seems like a simple implementation, so I might add it to Killer-Blog. There’s even a proposal spec out there, that suggests a more complex enclosure mechanism, allowing for relations between (multiple) enclosures per .