I think that's kinda the whole point of the Tractatus: much of philosophy (metaphysics and ethics, particularly) has no sense. Strictly speaking, they mean nothing.
Wittgenstein's early work inspired the development of modern analytic philosophy both in its use of formal methods and its claim that much of what was then considered philosophy was meaningless. The decades immediately following Wittgenstein were concerned with linguistic analysis (what the authors of these papers take fault with), while more contemporary philosophy has conceded to a kind of naturalism, appealing to the sciences.
If you place any value on modern analytic philosopher (even as a Popperian), you have to at least give Wittgenstein some historical credit even if the philosophical travesties of the logical positivists can be attributed to misinterpretations of the Tractatus.
With regards to decent philosophers with direct influence from Wittgenstein, what's your take on Kripke and Anscombe?
Anscombe wiki has:
For years, I would spend time, in cafés, for example, staring at objects saying to myself: "I see a packet. But what do I really see? How can I say that I see here anything more than a yellow expanse?"
I think that stuff is a dead end. We should solve problems we have, not question all traditions simultaneously for no particular reason.
By the way, I do think there are good philosophers, who made useful progress, but they are largely neglected. e.g. xenophanes, godwin, burke, feynman. (neglected as philosophers)
In philosophy a method proposed by Descartes to find the foundations of knowledge was to doubt everything that possibly could be doubted which includes the external world. Wittgenstein in his Tractatus similarly starts from a blank slate and tries to define and describe the world without crossing his own boundaries and definitions of what can be considered sensible to say (and fails. To objectively describe the world is an attempt to step outside it and his bounds of sense).
I would also like to note that this early is work very different from his later work where he completely rejected the Tractatus, writing with a different style and focus. His later work (especially Philosophical Investigations) has some extremely interesting ideas regarding language, its use and development which I believe would interest those working in the areas of semantic web and NLP.
Heh. Something about this comment seemed very familiar to me, and after a while I figured out what it was: the distinctive sound of xlnt aka curi. Yay web history!
While I have an enduring if inexplicable affection for you, and get that you weren't being sarcastic, the last thing I want to do is have an argument about Wittgenstein together :)
Edit: Besides, there can't be that many people who go on about Godwin, Burke, and Feynman.
His work seems to follow logically from Wittgenstein's point that a lot of philosophy comes down to the precise meanings of words.
The Chomsky hierarchy -- a method of classifying formal grammars. Seems computer science-y enough that you'll consider it as something real. http://en.wikipedia.org/wiki/Chomsky_hierarchy