OICQ

OICQ, which stood for "Open-ICQ," was an instant messaging client that gained significant popularity in China during the late 1990s and early 2000s. Launched in 1999 by Zhang Zhidong and his team at Tencent, it was one of the earliest and most influential instant messaging services in the Chinese market. OICQ's interface and functionality were heavily inspired by ICQ, a popular American instant messaging program at the time.

The service allowed users to communicate with each other in real-time, share files, and set up contact lists. Its widespread adoption was fueled by the rapid growth of internet usage in China and the relatively low cost of internet access. OICQ quickly became a dominant platform for online communication among Chinese internet users, fostering a sense of community and enabling social interaction.

However, the name "OICQ" eventually led to legal challenges. Mirabilis, the Israeli company that developed ICQ, sued Tencent over the use of a similar name and branding. To resolve the dispute, Tencent was forced to rebrand its service. In 2003, OICQ was renamed QQ, a change that ultimately contributed to the platform's continued success and its evolution into one of the largest instant messaging services globally. QQ retained many of OICQ's core features while introducing new functionalities and expanding its ecosystem.