The Semantic Web swamp
Swamps are interesting places, but not if you are looking to make rapid progress. They are an unfortunate hybrid between dry land and open water. A land vehicle will get mired in the muck. Ditto with a water vehicle. Sure, there may be patches of dry earth here and there or pools of water here and there, but not enough of either in a connected fashion to exploit either. This is how a lot of the current Semantic Web feels to me. There is simply too much technological "muck" that slows progress.
Just yesterday (and into today) I was following an email thread on the OWL list about the relatively simple concepts of subclass and superclass, but the discussion simply goes on and on because there is no clarity in the specifications. Maybe if somebody points you to the precisely right passage it will all become clear (or maybe not), but that should not be required.
Sure, there are books and tutorials and seminars and consultants, but none of that should be required, at least for the level that the technology is at today.
It is an open question whether tools or additional layers can be built on top of the current Semantic Web technologies that are sufficient to hide the "muck" of the "swamp." I am hopeful that is the case, but there are no guarantees.
Can we "flood" the swamp to turn it into a navigable lake or sea? Maybe.
Can we "fill" in the swamp to create solid, traversable dry land with the underlying swamp as an "aquifer"? Maybe.
Besides the concerns about usability of current Semantic Web technologies, there is the larger question of whether it is so complex even at this stage that even seasoned professionals may be unable to verify that Semantic Web constructions are technically correct and valid for their intended applications and not too fragile and are readily maintainable by other than their original developers. Five or ten years from now could we end up with a knowledge crisis analogous to the current banking crisis simply because we do not know the location or magnitude of risks?