vex, in answer, there is no reason for excessive pageins/outs on a properly programmed 64-bit OS with 4 GB of physical RAM and 10 GB of contiguous free space on the boot drive, with a properly programmed 64-bit app installed and running on the boot drive.  in regard to network activity, the main focus of OS X security breaches has been real or phony apps accessing the internet, some of which may have been written to defeat or fool security software (e.g. little snitch).