Technology stokes new Web privacy fears

Consumers worry about their Internet privacy. Politicians vow to investigate. And two of the nation's biggest tech companies, Google Inc. and Microsoft Corp., support federal legislation for data collection. So why isn't much happening? One reason is that legislators find the subject kind of confusing. For years, websites have assembled profiles of users consisting of personal preferences and activities. But as websites have increasingly been united in vast ad networks, the various profiles maintained by separate sites have combined to create more detailed and far-ranging portraits of users. Over the last year, moreover, some Internet service providers have begun experimenting with a practice that would offer even more detailed portraits of individuals. The technology, known as "deep packet inspection," allows ISPs to peer into the stream of data coming from a person's Internet line, a practice critics liken to wiretapping.