In her testimony, Leslie Harris of the Center for Democracy and Technology offered a good overview of what's at stake. She pointed out, as does our PIRG and CDD petition, that the new trend of behavioral targeting poses greater threats than traditional search advertising:

There is also a risk that profiles for behavioral advertising may be used for purposes other than advertising. For example, ad networks that focus on “re-targeting” ads may already be using profiles to help marketers engage in differential pricing.10 Behavioral profiles, particularly those that can be tied to an individual, may also be a tempting source of information in making decisions about credit, insurance, and employment. [...] The concerns about behavioral advertising practices are heightened because of the increasingly sensitive nature of the information that consumers are providing online in order to take advantage of new services and applications. Two data types of particular concern are health information and location information.

She also discussed the problem of behavioral advertising conducted right at the ISP, as opposed to ad network or website, level:

The use of ISP data for behavioral advertising is one area that requires close scrutiny from lawmakers. The interception and sharing of Internet traffic content for behavioral advertising defies reasonable user expectations, can be disruptive to Internet and Web functionality, and may run afoul of communications privacy laws.

Our previous blog on a joint letter to Congress with CDD, CDT and others on the company Nebuad and ISP behavioral targeting issues. Nebuad was also a witness today, as were Microsoft and Google.