what is this cookie (_op_aixPageId) i see it on many websites

hi recently we were scanning our website to comply with PCI standards a we found that there is an unsecured cookie created by our domain. we search our whole code base but didn't find any reference to a cookie named (_op_aixPageId). also found this on internet search -- http://ift.tt/1wl0fJI many sites have this cookie on their domains.

what this cookie actually is and what tool is generating it? any help is appreciated.