Adding Custom User Profile data based upon Categories

here is an example

//create the user category fields
add_action( 'show_user_profile', 'add_user_categories' );
add_action( 'edit_user_profile', 'add_user_categories' );

function add_user_categories($user ){
    ?>
    <table class="form-table">
    <tr>
        <th><label for="user_categories"><?php _e("User categories"); ?></label></th>
        <td>
            <?php
                $data = get_the_author_meta( 'user_categories', $user->ID );
                $args = array( 'hide_empty' =>0, 'taxonomy'=> 'category');
                $categories=  get_categories($args);
                if ($categories){
                    foreach ( $categories as $category ){ 
                        if(in_array($category->term_id,(array)$data)) {
                            $selected = 'checked="checked""';
                        } else {
                            $selected = '';
                        }
                        echo '<input name="user_categories[]" value="'.$category->term_id.'" '.$selected.' type="checkbox"/>'.$category->name.'<br/>';
                    }
                }
            ?>
        </td>
    </tr>
    </table>
    <?php
}

//save the user category fields 
add_action( 'personal_options_update', 'save_user_categories' );
add_action( 'edit_user_profile_update', 'save_user_categories' );

function save_user_categories( $user_id ){
    if ( !current_user_can( 'edit_user', $user_id ) ) { return false; }
    update_usermeta( $user_id, 'user_categories', $_POST['user_categories'] );
}

and go get the stored data just use:

$data = get_the_author_meta( 'user_categories', $user->ID );

and $data will be an array with all of the categories the user has selected.