// user_actions
auto_id = auto increment ID
type = a number (1 = photo upload, 2 = friend added, 3 = status post, 4 = so other action, etc..)
user_id = The id of the user who did the action
datetime = date and time
action_id = this could be the ID of the action, so if it is for a status post, it could be the ID of the actual status  post record

CREATE TABLE user_actions (
    auto_id         INT NOT NULL AUTO_INCREMENT,
    type            INT NOT NULL,
    user_id         INT NOT NULL,
    insert_datetime DATE NOT NULL,
    action_id       INT NOT NULL)
PARTITION BY RANGE(TO_DAYS(insert_datetime))
(
    PARTITION p0  VALUES LESS THAN (to_days('2011-06-01')),
    PARTITION p1  VALUES LESS THAN (to_days('2012-01-01')) ,
    PARTITION p11 VALUES LESS THAN MAXVALUE
);

-- Untested, but again should be close
ALTER TABLE t1 REORGANIZE PARTITION (pM) INTO
(PARTITION p20110101 VALUES LESS THAN (to_days('2011-07-01'),
 PARTITION pM VALUES LESS THAN MAXVALUE);