Here is the timeline: USB 1.0 was released in January 1996. Windows 98 launched in May/June 1998. Windows 98 was the first MSFT OS with native USB support. The first iMac was launched in August 1998. USB 1.1 was released in September 1998.
According to a June 1998 CNET article titled "Peripherals to surge with Win 98," Rob Bennett, group product manager of Windows 98 stated: "There will be a pretty impressive showing of peripherals this summer..There are 250 devices due to be launched around Windows 98 and 100 in development [to be] released in the next year..."
Looking through Google news archives for 1998, I see the following devices with USB support: Logitech scanners, Intel video cameras ("Create and Share"), Imation and Iomega high capacity drives, Kodak digital cameras, joysticks, modems, etc.
Hence, there was a collection of PC peripherals supporting USB around the time of the Windows 98 launch (in May/June) and the iMac launch later in the year (August).
Windows 98 was the first MSFT OS with native USB support
Windows 95 OSR2 supported USB (and FAT32) and IIRC was released in 1997, before the iMac. Another popular historical tale about the iMac is how it did away with floppy drives - however few people remember that the number one selling iMac accessory for the first few three years, with a huge attach rate, was the external floppy drove.
According to a June 1998 CNET article titled "Peripherals to surge with Win 98," Rob Bennett, group product manager of Windows 98 stated: "There will be a pretty impressive showing of peripherals this summer..There are 250 devices due to be launched around Windows 98 and 100 in development [to be] released in the next year..."
(http://news.cnet.com/Peripherals-to-surge-with-Win-98/2100-1...)
Looking through Google news archives for 1998, I see the following devices with USB support: Logitech scanners, Intel video cameras ("Create and Share"), Imation and Iomega high capacity drives, Kodak digital cameras, joysticks, modems, etc.
Hence, there was a collection of PC peripherals supporting USB around the time of the Windows 98 launch (in May/June) and the iMac launch later in the year (August).