But common lisp does come with vectors (make-array), hashtables (make-hash-table), and set-operators (intersection, union, pushnew, etc) that work on lists.

Also, Common Lisp (CLOS, in particular) supports multimethods (defmethod), contrary to what the author claims. And all of the special forms I saw in clojure have a counterpart in common lisp.

In fact, a lot of common lisp implementations (I like SBCL) have support for threading/asynchronous action built in. The one problem is that none of that is part of the ansi spec, so most multithreaded code won't be portable between implementations.

It isn't the language's fault that your teacher wouldn't let you use all these features.

What's distinctive about Clojure is not that it has them, but rather that it makes them first-class citizens in the way that lists are - i.e. provides a universal set of operators for manipulating them (or so I hear anyway). This is certainly a weakness of CL. I think this is the original point underlying the author's garbled statement, and it's an improvement specifically to CL that has nothing to do with the presence of arrays and hashtables in the language.

Edit: I realize this is probably obvious, but let's not confuse what this guy says about Clojure with what Hickey has to say. He's well aware of CL and doesn't make silly claims about it.

That's very true. I personally like clojure - and it does provide a lot of potential advantages to common lisp. I just don't think the author of this article understands them - he's just spewing bs.

Hickey does make a lot of valid points about the advantages/differences of clojure (http://clojure.org/lisps) though.

All practical Lisps (including Schemes) already have those data structures. In fact, many of them are required even by R5RS.