About the /players command

[Valeria]

Can anyone enlighten me on how this works, I mean post a table or something so that people will know the increased drop chances or XP gained?

[Rizzo]

Check out this thread. There're some goodies in there.

[Hrus]

Can anyone enlighten me on how this works, I mean post a table or something so that people will know the increased drop chances or XP gained?

XP gained 0.5x more for each additional player.
1*XP P1
1.5*XP P2
4.5*XP P8

For drops it has different impact on differnet monsters. I suggest reading my MF guide in the stickies. (Which I am sure was already advised to you)
MF Guide

EDIT: And monsters also get 0.5* more life for each additional player.