Why is "Voter registration in the United States" trending?

Wikipedia Overview

All US states and territories, except North Dakota, require voter registration by eligible citizens before they can vote in federal, state and local elections. In North Dakota, cities in the state may register voters for city elections, and in other cases voters must provide identification and proof of entitlement to vote at the polling place before being permitted to vote. Voter registration takes place at the county level in many states or at the municipal level in several states. Many states set cutoff dates for registration or to update details, ranging from two to four weeks before an election, while 25 states and Washington, D.C. have same-day voter registration, which enables eligible citizens to register or update their registration on the same day they cast their vote. In states that permit early voting, and have voter registration, the prospective voter must be registered before casting a vote.