http://www.extractiv.com/tour-semantic-on-deman.html - missing letter in '...deman.html'
http://www.extractiv.com/tour-semantic-on-demand - missing '.html'
Also, the pricing page says users need to buy a plus or premium subscription for access to Semantic On-Demand, but confusingly says the basic plan includes 'On-Demand access to 1,000 documents / day' - I presume you meant to emphasize the unlimited usage available with the premium plans.
I second, this seems interesting (and I would be really interested in seeing what you produce as "relations")
Suggestion: Can you put sample output on your homepage, so we can see what sort of semantic analysis you perform?
p.s. this tool doesn't have anything to do with the task.