EOS is another, 'new' cryptocurrency ... and just like you have a STEEM account, same thing with EOS... both blockchains require accounts in order for you to interact with them.
EOS doesn't stand for anything in particular, I think Eos is some Greek Goddess ... but beyond that can't tell you too much, ther than EOS is founded by the same person who made Steem and Bitshares, @dan Larimer...
Okay thanks.
In Greek mythology, Eos "dawn", pronounced [ɛːɔ̌ːs] or [héɔːs] is a Titaness and the goddess of the dawn, who rose each morning from her home at the edge of the Oceanus.
Eos had a brother and a sister, Helios, god of the sun, and Selene, goddess of the moon.
I thought if your are going to be promoting this new thing, you should know the history of the name. ☺