If you are using this constant in your wp-config.php file: define( 'ALTERNATE_WP_CRON', true ); then you will see something very similar to this: http://forum.ait-pro.com/?doing_wp_cron=1386111559.8750269412994384765625 in your Browser. Why does that occur? I have no idea, but if you are wondering why you are seeing doing_wp_cron in your Browser then this is the reason for that. It is also possible that a plugin that you have installed is using/defining this constant somewhere else other than in your wp-config.php file.
WordPress Codex Editing wp-config.php
http://codex.wordpress.org/Editing_wp-config.php#Alternative_Cron
Alternative Cron
Use this, for example, if scheduled posts are not getting published. According to Otto’s forum explanation , “this alternate method uses a redirection approach, which makes the users browser get a redirect when the cron needs to run, so that they come back to the site immediately while cron continues to run in the connection they just dropped. This method is a bit iffy sometimes, which is why it’s not the default.”
define( 'ALTERNATE_WP_CRON', true );
.
