Semantic Web and First Order Logic

Is it true or false that the semantic web 
limits the use of First Order Logic?

I realize that FOL has the undecidability 
problem, but is sufficient for everyday 
reasoning and is the most widely used 
logic in business.  One would think that 
the semantic web as a business application 
framework would use it profusely given that 
otherwise, the existing dominant base of 
relational business systems users would 
likely not want to be "on the semantic web".

I realize that is controversial and is 
deliberately so.  I am wondering if the 
semantic web is somewhat over-engineered.

len