The Semantic Web is not ...

Artificial Intelligence on the Web

it uses elements of logic ...
... but it is much more down-to-Earth
it is all about properly representing and characterizing metadata
AI systems may use the metadata of the SW

A purely academic research topic

SW is out of the university labs now
lots of applications exist already
big players of the industry use it (Sun, Adobe, HP, IBM, Nokia, ...)
much is still to be done