I've been using this site to organise my weekly game for over 13 years now, in which time the game has grown from a core 10 people playing 5aSide to a squad of only 100 players signing up for 7aSide. Keeping track of that many people's details and availability is only possible with a site like this. Setting up your game schedules, including time and venue, is simple and allows for easy repeating to keep the momentum going week after week.
It's also interactive for regular users, allowing them to track their goals across games as well as rating their fellow players. The latter is great for helping to select teams for the games. You can also be part of multiple squads so you can organise your Monday night game but sign up for that other game on a Thursday too. You can delegate organisational elements, such as selecting teams, to trusted users which is a welcome function for the overworked organiser.