Hi,
In the front-end, HikaShop can use a cookie to store the information about the "add to cart" popup.
That cookie will be removed from HikaShop in a future release but for the current versions (and if you have the setting to display "add to cart popup"), the cookie can be stored.
Otherwise, HikaShop use the Joomla session ; which use a cookie.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.