You may be asking what Races are, so let me explain. Races are (pretty much) "Titles" which are: Human, Elf, Dwarf, Hobbit, Orc, Half-Troll, Maiar, Valar, Nazgúl. They help distinguishing one Player from Another, which is clearly visible when you press the "Tab". Races are also used to create their own roleplay characters, you can find instructions for doing so at the link below:
Any other Functions?
Well yes, due to the McMMO Plugin on the Server, you can use it to Level up by gathering Experience through, for Example, Mining, which once you reach a specific Amount, grants you a higher Level, which gives you more Health-Points. All of the specific McMMO perks one can have is capped at a maxmimum of level 500.
There are also the MCMMO skills for combat, such as; Archery, Swords, Axes & Acrobatics. And the Archery skill is something special; Every 50 Archery MCMMO levels you deal 10% more damage.
Each MCMMO can be seen with /mctop [skill] or /mcrank. /mctop [skill] displays the top 10 players who have the highest level in that specific MCMMO skill. With /mcrank you can see your rank with every MCMMO skill on the server. Do /[skill] to display a text message saying your level & what your special abilities per skill are.