I appreciate that you like the site and want to clone it, but it's extremely poor form (and extremely misleading) to give your clone the same name.
The better version of my argument is "the product is not the same because it was not appropriately transferred between operators."
Of course this is all squishy and grey, since I don't believe DataTau filed a trademark claim, but moving forward with an identically-named product is still poor taste.
If you wanted to keep the project running, the first step would be to speak with the real site's maintainer to develop a plan.