No, that's not a metaphor for bloggers who use their feed readers to glean content from other web locations in order to post it on their own site, but that's a good guess.
These are bar coasters with an RSS theme, for a truly geeky cocktail hour.
Why? Because trying to explain how RSS works to your non-techie friends requires at least a couple of stiff drinks, that's why.
Feed and drink with these RSS-themed coasters , via ForeverGeek