A casual conversation about a hypothetical use of the World Wide Web
generated a question about what is legal and what is not.  Given the
breadth and level of expertise on this list, I thought I would ask the
question here.

Suppose there was a way to place an intercept on the Web data stream,
perhaps on routers or switches along the transmission path.  For
example, you might be browsing a site and all of a sudden get a new
window opened asking you to buy or do something.  This was generated
somewhere along the data stream independent of any web site or ISP.

Would this be illegal?  Given the borderless nature of the Internet, who
could possibly regulate and prevent this activity?  Is it technically
feasible?

Rob Joseph