Hilariously, without Net Neutrality, this particular article might never been seen...
Those early rules were largely voluntary but the FCC did take companies to court to enforce them with varying levels of success. It was this variability and a judicial erosion of what was considered permissible along with some fairly egregious shenanigans by internet service providers that pushed the Obama administration to formally reclassify broadband as a telecommunication service to put back in place net neutrality rules that stood before in the days of dial-up.