The title is a misnomer. The Internet is just a side in the plot of this movie, which is quite decent actually, as far as suspense thrillers go. The movie starts off really badly and for the first 30 minutes or so, it really drags. The action starts when a sexy computer programmer, Angela Bennett (played by Sandra Bullock), finds that her identity has been erased and replaced by a Ruth Marx who has a criminal record a mile long. All because Bennett got hold of a floppy disk she shouldn't have. With the floppy, Bennett is able to access the information on various federal and corporate systems on the Internet. The owners of this floppy are called "cyberterrorists" and they stop at nothing to preserve their secret. The movie essentially revolves around the things they do in order to get rid of Bennett, and how Bennett is able to finally defeat them at their own game.
This is one of those Robert Ludlum style movies, where it seems no one can be trusted. When Bennett's identity is stolen, everyone she turns to is either killed or turns to be untrustworthy. The ups and downs are handled well---there is some uncertainity about who is trustworthy. Bullock's the star of the show, and she handles it well. I thought the other people were okay.
Many people might doubt the authencity of the plot, but I think it should be taken in a positive light. The reason the so-called cyberterrorists are able to access and modify vital information (from medical records to fingers) is because they are the ones in charge of the security of the system. That is, they sell a security program which allows them a backdoor. While I think it would be pretty hard for an individual organisation to accomplish what they did, I do think it is possible for the goverment to do the same. We have seen at least one similar situation with the Clipper chip, where the government has a backdoor to any encryption. I think encryption, when used properly, is a easy and extremely secure way to keep information safe even from the most powerful attacks. In the case of the Clipper chip, even the secure information is amenable to government modification and intervention. Similarly, rumours about what Microsoft does is another example. Given the explosion of PCs getting on the Internet, particularly using Microsoft software, what is to prevent the software from transmitting this information to the corporate agency?
That is where I think the main hole in the plot is: while this might be possible, I don't think it's probable simply because, at least at present, there are too many vigilant people on the 'net.