Which old digital money let people pay each other, not as a sale?

Research question: Which pre-bitcoin digital money service let users pay each other in units without any cash changing hands, and how would a reader tell that apart from a sale?

The facts describe electronic money as a non-personalized payment product that can circulate separately from the banking system ¹. The records show that Yandex.Money began operating on 24 July 2002 as a joint project of Yandex and PayCash ², with PayCash supplying the technology platform ³. The facts do not state that Yandex.Money let users pay each other in units, so that match is an inference rather than a verified finding. The records show that an electronic money payment requires only the recipient's details, whereas non-cash transfers are always personalized and both parties' details are known ⁴. The facts do not describe how a sale works, so they only partly answer how a reader would tell a unit transfer from a sale.

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