True, it used USB (like the PowerMac G3 before it)
The iMac was, in fact, the first Apple computer available with built in USB ports.
The iMac was shipped in August 1998. The Powermac G3 did not have USB ports until the Blue & White series which were released in January 1999. The Powerbooks finally got their USB ports with the Lombard series in May 1999.