I'm quite sure that I can separate, if I'm reading Ars Technica or ReadWrite, even when not explicitely being told so, but while reading textual content of an article (with a possibility of seeing a photo, if it was included in the RSS-feed) different sources don't _feel_ different.
When I see the name of a source like "TechCrunch" I become aware of the attributes I've attached to it in my mind and thus I partially know what to expect from it. However, that is not enough to separate jokes made by Business Insider's article writers from TechCrunch's article writers. My mind wants more hints about the context (sensory cues, usually visual).
I'm not very keen to install tens and tens of different applications just to "be more in it", but I don't like vanilla RSS-feeds either (even with special effects).
It is virtually impossible to not ruin the experience of using a RSS-aggregator, if the subscribed feed doesn't contain any photos. I just subscribed to Phys.Org's RSS-feed through Google Currents and it was horribly boring to read the text snippets (full articles available on the actual website only).