The end of the sandbox

Originally, we have provided TaxonConcept's sandbox as a testing area for persons interested in the functionalities of TaxonConcept. The sandbox was a complete mirror of TaxonConcept, it was intended to be the site where people could just play around with the tool without obligations and risks after a short online registraton.
We have offered free access to the sandbox for several months, but we found that despite comparably many people have registered, none of them did really use it. After more than one year, there was only a hand full of testing entries. After comparing this little impact with the efforts required to maintain the sandbox we decided to close the sandbox.
I now wonder why that many people registered to the sandbox and apparently have decided not to use it. OK, TaxonConcept is not an easy tool, but we have now two students working with it and it took just one or two days to train them.
Probably people who registered simply did expect something completely differend to receive after clicking on the 'register me!' link, maybe something like a newsletter?