inc/class-Iac_Profile_Settings.php
public function add_custom_profile_fields( $user ) {

		$user_settings = apply_filters( 'iac_get_user_settings', array(), $user->ID );
		$nonce         = wp_create_nonce( 'iac_user_settings' );
	?>
		<h3><?php _e( 'Informer?', $this->get_textdomain() ); ?></h3>

		<table class="form-table">
			<tr id="post_subscription">
				<th>
					<label for="post_subscription_checkbox"><?php _e( 'Posts subscription', $this->get_textdomain() ); ?></label>
				</th>
				<td>
					<input type="checkbox" id="post_subscription_checkbox" name="post_subscription" value="1"
					<?php checked( '1', $user_settings[ 'inform_about_posts' ] ); ?> />
					<span class="description"><?php _e( 'Inform about new posts via e-mail, without your own posts.', $this->get_textdomain() ); ?></span>
				</td>
			</tr>
			<tr id="comment_subscription">
				<th>
					<label for="comment_subscription_checkbox"><?php _e( 'Comments subscription', $this->get_textdomain() ); ?></label>
				</th>
				<td>
					<input type="checkbox" id="comment_subscription_checkbox" name="comment_subscription" value="1"
					<?php checked( '1', $user_settings[ 'inform_about_comments' ] ); ?> />
					<span class="description"><?php _e( 'Inform about new comments via e-mail, without your own comments.', $this->get_textdomain() ); ?></span>
					<input type="hidden" name="iac_nonce" value="<?php echo $nonce;?>" />
				</td>
			</tr>
		</table>
	<?php }
public function add_custom_profile_fields( $user ) {

		$user_settings = apply_filters( 'iac_get_user_settings', array(), $user->ID );
		$nonce         = wp_create_nonce( 'iac_user_settings' );
	?>
		<h3><?php _e( 'Informer?', $this->get_textdomain() ); ?></h3>

		<table class="form-table">
			<tr id="post_subscription">
				<th>
					<label for="post_subscription_checkbox"><?php _e( 'Posts subscription', $this->get_textdomain() ); ?></label>
				</th>
				<td>
					<input type="checkbox" id="post_subscription_checkbox" name="post_subscription" value="1"
					<?php checked( '1', $user_settings[ 'inform_about_posts' ] ); ?> />
					<span class="description"><?php _e( 'Inform about new posts via e-mail, without your own posts.', $this->get_textdomain() ); ?></span>
				</td>
			</tr>
			<tr id="comment_subscription">
				<th>
					<label for="comment_subscription_checkbox"><?php _e( 'Comments subscription', $this->get_textdomain() ); ?></label>
				</th>
				<td>
					<input type="checkbox" id="comment_subscription_checkbox" name="comment_subscription" value="1"
					<?php checked( '1', $user_settings[ 'inform_about_comments' ] ); ?> />
					<span class="description"><?php _e( 'Inform about new comments via e-mail, without your own comments.', $this->get_textdomain() ); ?></span>
					<input type="hidden" name="iac_nonce" value="<?php echo $nonce;?>" />
				</td>
			</tr>
		</table>
	<?php }
Add cutom profile fields

@wp-hook show_user_profile
@wp-hook edit_user_profile

@since  0.0.2
@uses   _e, checked

@param  array $user

@return void