Status Conditons are things thaty can affect the player and mobs by dealing damage and other effects that may enhance or limit what you can do.
While on fire, you will take damage regulary until it wears off, like the normal minecraft fire. That wont stop you from spreading it to mobs, though. Get close and share the love!
While stunned, you will move slower then average. This will give mobs that you can normally outrun an advantage, so watch out! Caused by heavy mobs, like the iron golen or the Troll.
While bleeding, you cant be healed by average health regen, (from full hunger bar) Potions of healing, or a Health Dispenser. Caused by a skeletons arrow, a wolfs sharp teeth, or even a spiders fangs.
While frozen, you cannot move. You can still attack mobs, but a bow draw will be slower and the sword wont swing as fast. If a player hits you, it will chip off some of the ice. Ask your friends to chip the ice off with their best attacks. Ice will wear off after 20 seconds.
While cursed, your vision will be dissorted, slightly modified (AKA finding diamond randomly when its really stone) and other strange effects. This strange effect has a chance of coming from an enderman, the ender dragon, and other end mobs.