The Ferguson protests are a good example. It's already resulted in some sweeping changes to their municipal court system[1], which has been described as, "One Big Shakedown Racket Targeted at Black People"[2]. These are changes the activists and lawyers had long sought, but was refused by the City Council until these protests made that untenable.

It is continuing to force the local police to a higher standards of accountability and transparency then they would have done without[3]. Additionally, this along with the recent national attention to other unarmed black men being shot by cops, has played a huge role in getting police officers equipped with dashboard and body-mounted cameras[4].

eta: grammar

[1] http://news.stlpublicradio.org/post/policymakers-eye-big-cha...

[2] http://www.slate.com/blogs/the_slatest/2014/09/04/st_louis_f...

[3] https://en.wikipedia.org/wiki/Shooting_of_Michael_Brown#Poli...

[4] http://www.nytimes.com/2014/09/28/us/todays-police-put-on-a-...