2004.01.15 00:11 "Re: [Tiff] http://www.libtiff.org/", by Bob Friesenhahn
I suggest trademarking "libtiff" (may be as simple as adding (TM) beside libtiff on the web site, and a trademark statement)
No, it is not that simple to trademark a name - at least not in the USA. Also, international lawsuits are not as easy as you think...
You are talking about a registered trademark (R). It takes at least a year to get a registered trademark, and the registration request will be rejected if your lawyer is not responsive, or it is believed that the trademark is already in common use.
Most trademarks are not registered and are denoted with (TM). unregistered trademarks are supported by actual use, and the initial usage date. Unfortunately, defending unregistered trademarks usually takes legal action.
Almost all lawsuits are more painful than can be imagined.
The first step should be determining who the ISP is, and convincing the ISP that their customer is doing something illegal.