Rainey Reitman of EFF writes:
Earlier today, Mozilla announced plans to incorporate a Do Not Track feature into their next browser release, Firefox 4.1. Google also announced a new privacy extension today, but we believe that Mozilla is now taking a clear lead and building a practical way forward for people who want privacy when they browse the web.
I think these developments actually caught a number of privacy advocates by surprise.
Read more about the new options and how Do Not Track works on EFF.