I was contacted some months ago by a fellow SL deshi that a web page ( http://gameofgo.net/all-go-servers) is using SL content in violation of the Open Content License.

I contacted the owner of that website, but never got a reply. The only recourse left would be to contact the ISP and ask them to either notify their customer or pull the plug. I am hesitant to do that.

What kind of action do you think is warranted?

ps: The license on SL allows copying and using the material, but only if the license conditions are met.

My feeling is to let sleeping dogs lie, i.e. do nothing at this point.

I'm making the assumption it is just the one page you've linked to. Just keep the record of the email indicating you objected, but don't chase the ISP. Once you start to demand retraction by the ISP, you have to put in the time and effort to follow it through, and deal with any push back from the site owner. The amount of effort compared with the small size of the infraction seems unjustified to me.

I'm not seeing this as a point of principle situation, where something must be defended against all odds. Standing on principle always carries the risk of being foolish in practise, despite the fact that you have right on your side. So for me, I'm not seeing this as the tip of an iceburg, or a wedge situation. I see it as one individual has done something they shouldn't. It's like children stealing sweets from the corner shop. Don't ignore it, but don't over-react either.

( If it is more than the one page, or repeated behaviour after having the issue pointed out, I would see the issue very differently. )