Dive summary: 

• As part of IAB's annual Long Tail Alliance Fly-In, 60 small web companies will be at the U.S. capitol in efforts to stop Mozilla's "do not track" policies and technology. 
• Small publishers like JoyofBaking.com and Ikeafans.com depend heavily on revenue from ad networks which use cookies to function and can't afford to be cut off. 
• While Congress cannot prevent Mozilla from doing anything, they can use their power in an effort to persuade the browser; four GOP lawmakers, Reps. Mike Pompeo (Kan.), Marsha Blackburn (Tenn.), Walter Jones (N.C.), and Jeff Denham (Calif.) have already sent a letter to the nonprofit Mozilla asking them to reconsider their plans as it favors large publishers over smaller ones. 

From the article: 

"'The third-party cookies that Mozilla Firefox would block are what allow the U.S.-based Internet publishing industry to sustain original, free content on thousands of small business websites in every corner of America,' the four lawmakers wrote.'"