|This question is inspired (i.e. stolen) from Alex Miller at http://twitter.com/puredanger/status/19451154832293888.|
Whether you like Clojure or not, it's difficult to deny that it's generated a lot of buzz for Lisp in general. As a nice side-effect, there has been a rise in the number of organizations willing to take a chance on using Lisp for their products and services.
I see some parallels between Lisp and Prolog as families of programming languages. There are likely as many hobby implementations of Prolog as Lisp. Likewise, there is a gross misunderstanding of Prolog and Lisp among the general programmer population. Also, it's unclear how to get started with Prolog and Lisp concerning: implementations, IDEs, documentation, and gurus. To varying degrees, Clojure provides a solid answer to these common misunderstandings for Lisp, but what about Prolog?
Where is the logical successor to Prolog?
Some potential candidates are: Oz, Mercury, some sub-Prolog implementation embedded in another language, some other logic language altogether (e.g. Datalog).