If an e-shop uses promo codes - almost every user will do a quick google search for one.
Based on this logic - KuponuKodai.lt - is optimised for search engines and organically catches all these users (by providing verified promo codes). And even better, these users usually subscribe to our mailing list and aggregated promo codes are delivered directly to returning customers. So it's a win-win-win scenario.
E-shop owner is happy - he didn't lose his client and the client is more likely to shop repeatedly.
Client is happy - as he received a discount and is always informed about new great deals.