Year-End Countdowns available:
2002, 2003, 2004, 2005, 2006

Other Countdowns available:
Y100 Top 300 Songs of the 90's (Sep. 2000)
Y100 Top 300 Songs of All-Time (Jul. 2004)

On February 24, 2005, at 11:50 PM, WPLY 100.3 signed off on a ten-year run of modern rock with "Alive" by Pearl Jam. This left Philadelphia the largest U.S. market without an alternative radio station. Owners Radio One moved the urban/hip-hop station WPHI (the Beat) from 103.9 to the stronger 100.3 signal.

Angered listeners immediately flocked to the website Y100rocks, set up by program director Jim McGuinn and the staff right before the format switch, to vent frustrations and share memories. Nearly a hundred thousand names were on a petition to bring back their beloved station, hoping to follow the lead of WHFS in Baltimore, which was taken off the air and then later put back in the Baltimore area and online due to public demand. For listeners craving their needed alternative music and former DJ's, the site broadcasted online in a format slightly more adventurous than its land-based predecessor.

On August 1, 2006, the online stream was picked up by WXPN, a public radio station operated by the University of Pennsylvania. Live broadcasts are held every Wednesday, Thursday, and Friday nights as well as 24/7 online.