I've created a new SGF viewer to replace the old broken Jave-based one. This one should be much light-weight, look better and provide additional functions. This is now the default SGF viewer on Go4Go. But one can still choose to switch to the Eidogo player which is slightly more portable on old computers.
Click the ' Diagram code ' link below the board to generate a text representation of the current board position. This can be copy/paste into any posts on Go4Go (or other compatible sites) when discussing board positions.