FCC "ABCs" Act of 2017 This bill amends Communications Act of 1934 to direct the Federal Communications Commission (FCC), in the case of a proposed or final rule (including a proposed or final amendment to an existing rule) that may have an economically significant impact, to include in the notice a cost-benefit analysis demonstrating that the benefits outweigh the costs, recognizing that some benefits and costs are difficult to quantify. An "economically significant impact" is defined as an effect on the economy of at least $100 million annually or a material adverse effect on the economy, a sector of the economy, productivity, competition, jobs, the environment, public health or safety, or state, local, or tribal governments or communities. The bill prohibits any appropriations for the express purpose of carrying out such analysis and notice requirements. The FCC must presume, absent clear and convincing evidence to the contrary, that: (1) forbearance requirements are met when determining whether to forbear from applying any regulation or provision under such Act to a telecommunications carrier, service, or class; and (2) regulations considered in each biennial regulatory review are no longer necessary in the public interest as the result of meaningful economic competition between providers of telecommunications service.