Over there on the right, in the list of links to other sites, you’ll find a category called “Je Ne Sais Quoi.” Per the American Heritage Dictionary online at the Bartleby site, this phrase — literally, in the original French, something like I know not what — means, “A quality or attribute that is difficult to describe or express.”
I came up with that category because every now and then I come upon a site which is so striking — in its writing or conception, not necessarily its look — that I know I’ll want to revisit it from time to time, if not daily, just to see what its proprietor might be up to at the moment. Often, these sites lead me (through their blogrolls, especially) to other such sites, and I come to realize that the site I first found isn’t unique at all. It may not even be the “best” (whatever that means) of its type. But the first one goes into the Je Ne Sais Quoi basket anyway, where I expect it to stay.
The very first site for which I couldn’t figure out a decent other category, and hence came up with this one, was the “Dealing in Subterfuges” blog, written by the pseudonymous “Jordan Baker” — perhaps (but not probably) coincidentally, a character in Fitzgerald’s The Great Gatsby.