ICQ, which used to be a very popular messaging app for a short period in the 90s and the early aughts, only has a month left before it joins the other apps and software of old in the great big farm in the sky. It will stop working on June 26, according to it website, which also encourages users to move to VK Messenger for casual chats and to VK WorkSpace for professional conversations. ICQ came into the picture at a time when most people were using IRC to chat. IRC, however, was mostly meant for group conversations — ICQ made it easy to communicate one-on-one.

Users who signed up for an account got assigned a number that grew longer as time went on, because it was issued sequentially. The shortest numbers had five digits, which means users who got them were there at the very beginning. ICQ peaked in the early 2000s when it reached 100 million registered accounts. And while it didn’t take a long time for AIM, Yahoo Messenger and MSN Messenger to eclipse its popularity, ICQ’s iconic “uh-oh!” notification sound remains memorable for a lot of internet users during that era.

ICQ, derived from the phrase “I seek you,” was developed by Israeli company Mirabilis. It was then purchased by AOL and then by the Russian company Mail.Ru Group that’s now known as VK, which has its own social networking and messaging services.

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