Open Transport vs. QuarkXPress -- I've heard reports of two conflicts between Open Transport 1.0 (shipped only on the Power Mac 9500s) and QuarkXPress. If you have an XTension installed that receives the XT_NETRECEIVE opcode, QuarkXPress will hang on launch. I doubt there's any easy way to determine if you have such an XTension loaded other than by empirical testing. Apparently, Open Transport 1.0.1 fixes the problem. Even with Open Transport 1.0.1, if you have either the printer port or the modem port chosen as your network connection in the AppleTalk control panel, QuarkXPress will hang on launch if any XTensions that use network serial copy protection are installed. [ACE]
Monitor Network Throughput with VirusBarrier X6
Concerned about how much data is coming into or leaving your Mac? Try VirusBarrier X6's network monitoring tools, which include a Traffic window, a standalone Traffic Monitor application, and even a screensaver that displays real-time traffic information.