Operating on-line marketplaces for sellers and buyers of goods and/or services; Providing a website featuring an online marketplace for exchanging goods and services with other users; Provision of an on-line marketplace for buyers and sellers of goods and services; Provision of an on-line marketplace for buyers and sellers of Professional services; Provision of an online marketplace for buyers and sellers of downloadable digital keys authenticated by non-fungible tokens (NFTs); Provision of an online marketplace for buyers and sellers of downloadable digital OTP (one-time passcode) authenticated by non-fungible tokens (NFTs); Provision of an online marketplace for buyers and sellers of downloadable image files authenticated by non-fungible tokens (NFTs); Provision of an online marketplace for buyers and sellers of downloadable music files authenticated by non-fungible tokens (NFTs); Provision of an online marketplace for buyers and sellers of downloadable video files authenticated by non-fungible tokens (NFTs); Provision of an online marketplace for buyers and sellers of goods and services; Retail store services featuring human resources provided via downloadable mobile applications