The fact that Webtaggers has no customers apart from NETP may indicate that (a) NETP made a poor buy or (b) that Webtaggers is poor at marketing.
However, let us assume that the Webtaggers technology is worthwhile. Your question about its value to NETP comes down to the price. NETP is paying $500,000 for a licence. Presumably, NETP wants Webtaggers to continue with enough staff in order to fulfil its contract to NETP and for the technology to finish up in the hands of a company that will continue to give NETP access to it. Otherwsie NETP has to find an alternative. (It may have already delayed the launch of the NETP "heads up" product").
I would guess that a buy-out price of $500,000 to $1 million would be a good deal for NETP. Any price after that and NETP would have to feel that it could generate sales of the Webtaggers product from its own customer base or a new marketing effort - alternatively NETP would want to take Webtaggers off the market so that NETP could use it exclusively.