<Do you think that we can collect fees for past infringement or only for future infringement?>
I am confident that TPL will claim past infringement in any license negotiation or litigation. Whether it will be collected is not easily determinable. One would need to know the extent to which a company infringed and for how long. Since we are not privy to that kind of info, we can only assume that if the fees are going up, then we probably are collecting for past infringment. But no way to know for sure.
IMHO, Opty