WinGate is a proxy server firewall software package that allows you to share a single (or multiple) Internet connections with an entire computer network. The Internet connection shared by WinGate can be of nearly any type, including dial up modem, ISDN, xDSL, cable modem, satellite connection, or even dedicated T1 circuits.
Wingate is similar to a Proxy Server which connects a computer to another server through it on port 23. In fact, it's just a telnet connection. The Wingate will let anyone on the network access the Internet or connect through it to other sites. Due to poorly configured wingates and Administrator's incompetence, there's a lot of wingates that will let anyone on the Internet connect through them, instead of limiting access to people from the local network. Opening the way for anything from an IP spoof on ICQ or irc to full scale abuse. Such wingates are called "Open Wingates" and usually last from anywhere from a few days to maybe a few months until an Administrator either discovers it or gets complaints about some "mysterious" users doing something they shouldn't be. Most likely in that case it's someone connecting over the Internet.
The only benefit for administrators is the ability to put multiple users through the same connection. The problems with it clearly outweigh the benefits. If anyone is going to set up their own wingate, I'd suggest strongly that you know what you are doing and make sure that is configured securely so that only those that are meant to use it, are the ones using it. Another more secure WinGate-like software is SyGate.
In most of the cases the logs of the wingate server are cleared usually after every 48 hours. Most businesses and ISP's (especially the big ones) just don't have the need or the resources to log every single thing that happens on their wingate servers.