Determine Which Process Is Hogging Your Modem
Users on modems may often see their upload light blinking away erratically and wonder 'Which process is sending all that data?'. Port Explorer makes this easy to see - simply ensure that Port Explorer's refresh rate is relatively fast (1-5 seconds is recommended) and then visually browse through the 'Sent' column - what you're looking for is a socket with a Sent count that is continually incrementing. There'll probably only be one that is rising noticeably, this is almost certainly the process that is hogging your modem and sending all that data. To see what data is being sent, simply use the Socket Spy utility.

Preventing A Process From Being Able To Send Data
Preventing a process (or even an individual socket) from being able to send (or receive) data is very easy with Port Explorer -- simply right-click on the process or socket you wish to block, and click on the 'Block Sending' menu from the Socket or Process menu branches.

Slow\restrict the speed of a socket or process
The Bandwidth Throttling capability of Port Explorer allows you to restrict the speed that a socket or process can send and\or receive data - a capability exclusive to Port Explorer. Simply right-click on the socket or process you want to restrict, choose the Socket or Process submenu, then select Max Send Speed or Max Recv Speed.

Closing An Established Connection
Port Explorer gives you the precise ability to terminate/close individual sockets (without affecting or terminating the target program). To close a connection, simply right-click on the socket you wish to close, and select the 'Kill Socket' menu from the Socket menu branch.

Detect which country an IP address belongs to
Port Explorer has automatic IP-to-Country resolving (look in the Country column in the main window), but you can also use this feature on-demand simply by using the Lookup utility (from the Utilities menu), and selecting IP to Country.

Find The Owner Of A Domain
So you've seen a strange connection to your machine from a machine such as 'pc1.xyzhost.com'. This begs the question - who is xyzhost.com, who owns the domain, and who can I contact? The WHOIS utility that comes with Port Explorer makes obtaining this information this very easy. Simply start the Whois utility and do an Automatic Search for xyzhost.com. Within a matter of seconds you'll be presented with owner/contact information about that domain, including an email address to contact.

Sortable Column Headers
A very simple yet powerful feature - Port Explorer's built-in automatic sorting capability allows you to easily sort the data being displayed (ie. from lowest to highest, from newest to oldest, in alphabetical order, etc.). For example, clicking on the Local Port column will cause all data to be shown in the order of the local port corresponding with each socket, showing the ports with the lowest values at the top . Clicking on Local Port again will reverse the order, showing the ports with the lowest values at the bottom. Clicking on the 'Creation' column allows you to easily see the sockets which were most recently created - they'll be at the top of the list. This is a very simple feature yet it makes viewing socket data dramatically easier - take advantage of it! 

Interchangeable Column Headers
You can easily change the position/order of the column headers in the main Port Explorer display (such as 'Process', 'ProcessID', 'Protocol' etc.) simply by dragging them with your mouse. For example, if you're not very interested in how many bytes have been sent/received, you may wish to move the 'Sent' and 'Received' columns to the far right. The column orders are automatically remembered by Port Explorer.

Extended Whois Information
The next time you use Port Explorer's Whois utility, change the search from Automatic over to a manual server, such as "Australia (.au)". Enter "help" as the search query, and press the Search button -- the Whois server should return extended information about different ways to query it's database. This allows you to then perform more precise searches. Other queries such as "?" may also work - commands vary from server to server.

Saving/Loading Socket Spy Packet Logs
The data logged by Socket Spy is automatically saved to capture.bin in your Port Explorer directory. You can make a backup of this file at any time you wish, and can also overwrite capture.bin with an existing copy to restore previously-captured data.

Freeze The Port Explorer Display
There may be  many times when you use software (not just Port Explorer) that you wish you could freeze the program so that you could take a snapshot, such as a screen capture. Port Explorer makes this easy - simply press F2 (or select 'Pause Display' in the Settings menu), and Port Explorer will stop updating it's display, essentially running in paused mode. Then you can easily make a screen capture or even save the table data by selecting 'Save Table' from the File menu. Pressing F2 again will unfreeze and allow Port Explorer to update the display.

Command Line Options
To use these command line options you must specify them when you start Port Explorer (by modifying the shortcut to Port Explorer, or by implicitly declaring the parameters from the command line).
-m        Adding this will make Port Explorer start minimized to the systray as long as you have "Minimize to Systray" option enabled in Port Explorer.
Example: d:\program files\port explorer\portexplorer.exe -m

Log Path
By default, Port Explorer saves the network activity logfile to PELOG.TXT in the Port Explorer directory. You can manually override this by creating a REG_SZ registry value called "Log Path" in HKEY_LOCAL_MACHINE\DIAMOND COMPUTER SYSTEMS\PORT EXPLORER\, the value being the full path to the desired logfile (ie. c:\mypelog.txt)