A lot of residents have (for some years) used the eye-in-hand logo to mark "pure SL content" generated by residents. I'm told there's a bundle of such logos at Svarga.

This is, of course, at odds with Linden Lab's perception of the mark which they seem to intend to indicate that something or someone is an official Linden Lab thing. That is certainly how they have enforced the mark in the past.

It's a bit strange that there's no single widely recognized icon that can be used to indicate Second Life that isn't under a set of restrictions that make it difficult to actually refer to Second Life graphically.