ESMS PBeM Soccer Manager system was an engine for PBeM soocer manager games created in 1999 by Eli Bendersky and Igor Oks. It gave the tool for soccer fans to run their own leagues with friends using e-mails to exchange data. It was one of the first such systems and, since it was free, quickly became standard among users. The rules were simple - all users had their team rosters with their player, for each round they were preparing the input files containing their squad for next round and sent them to the game master, who runned ESMS and was sending back the results, also via e-mail.
In times when Internet connections were slow and access to Internet not as common as today it was a brilliant idea - very low amount of data had to be exchanged (only text files) and well configured maillist was all that was required to run the game. Number of player skills were limited to only 5 (shot-stopping, tackling, passing, shooting and agility), but with options to set tactics, formations and auxiliary orders it was almost as much as any PBM game had to offer and ESMS was faster, cheaper and any number of rounds could be player without delays.