VAHEGURU JI KA KHALSA, VAHEGURU JI KI FATEH
1) Multi-tasking - you can chat, browse websites, read the news, watch a video and listen to audio all at the same time from the same machine. And all this you can do while communicating with multiple people simultaneously.
2) The "In" Thing - chatting with friends on Facebook/MSN/Skype is the cool thing to do - phones are "old skool" and only allow for audio. Internet allows you to post pictures, video, status updates and generally waste time in a more comprehensive manner.
3) Devolving Of Society's Communication Abilities - the world is les and less social and face to face these days. People prefer hiding behind technology for communication rather than face to face interaction. "Everything" can be done online, so why bother making the effort to communicate in person. People in the same house at times will message each other online rather than go talk face to face.
4) Laziness - part of #3, why bother to make a physical effort to go and talk to someone when you have a computer/cell phone in front of you all the time - just message them on the internet.
Some things off the top of my head. As a Gursikh said, Maya serves those who use it for Gurmat, but makes servants of those who are stuck in it. The internet can be used to do huge amounts of good (after all, this website is on the internet, as well as many others) IF it is used for Gurmat. The problem is that the Internet presents a whole array of temptation and manmat that is very difficult to resist. Internet chatting and whatnot is all a part of that - if you chat for Gurmat, then great. If you chat and get stuck in manmat - you will compound your manmat by multitasking it.