In 1996, talking to someone online meant shouting into the scrolling chaos of an IRC channel. Then five Israeli developers, Yair Goldfinger, Sefi Vigiser, Amnon Amir, Arik Vardi, and his father Yossi Vardi, founded Mirabilis and released a small free program called ICQ. With no marketing budget and nothing but word of mouth, it gave every user a permanent account and a direct, private line to one other person. Each account carried a sequential user identification number, the UIN, starting at 100,000. A six digit number became proof you had been there at the beginning.

This episode traces the full life of ICQ: the 1998 sale to AOL for $287 million upfront plus $120 million tied to performance, the climb to 100 million registered users by 2001, and the ads and bloat that drove Americans away. It follows the service east after its 2010 sale for $187.5 million to Digital Sky Technologies, where its lightweight protocol suited slow, metered connections, and ends with the brief notice that shut it down on June 26, 2024.

• AOL already owned AIM, but AIM’s strength was tied to American dial-up subscribers. Buying ICQ secured the borderless global audience it lacked.
• In 2001 contact lists moved from the user’s hard drive to AOL’s servers, a convenience that also made leaving the platform far harder. In 2002 AOL Time Warner was issued a United States patent for instant messaging itself.
• Power users fled the ads for third party clients such as Pidgin and Miranda NG, built by reverse engineering the OSCAR protocol. ICQ repeatedly changed its servers to lock them out.
• In Russia, low digit UINs sold for more than 11,000 rubles, and in 2021 a WhatsApp privacy scare sent ICQ downloads in Hong Kong up 35-fold in a single week.
• A 2018 Novaya Gazeta analysis of court sentences indicated Russian intelligence could read ICQ correspondence, and a 2023 Brazilian investigation tied lax moderation to the sharing of child abuse material.