Critical 's hit "
Since U Been Gone".|right The song received universal acclaim.
IGN gave a positive report stating "Pink keeps the mainstream, highly accessible pop trappings in full effect with "Who Knew," further making her whole visual stance that much more hilarious (the contrast of a punky, bad girl doing slick pop may be "rebellious" to some, but frankly it just seems contrived). Despite the slickness, the song does reveal Ms. Pink to have a wonderfully full and mesmerizing voice and makes the fact that she's a star understandable." John Murphy from
MusicOMH wrote that the song "is perfect driving, anthemic pop."
Stylus Magazine said ironically that "It’s “
Since U Been Gone” spinning its wheels at half-speed, mutedly wondering where the tune went." Sal Cinquemani from
Slant Magazine wrote that "Songs like 'Who Knew' and 'Long Way to Happy', though good, sound more
hair metal than
punk", while also noting that it "follows the steps of
Clarkson's recent hits."
Billboard magazine, in its second review of the song (to accompany the U.S. re-release), called it "another cool, smart, plenty passionate melodic jewel about the death of a friend and/or friendship, with an instantly identifiable, quick-to-the-point, singalong track—maintaining Pink's stance as the smartest female millennium-era singer/songwriter, dazzling in star quality as alterna-pop's premier princess." The song had debuted at number thirty-six on the
New Zealand Singles Chart, and eventually rose to number eleven, just missing the top ten. The song spent a total of twelve weeks on the charts. In the European markets, the song was generally successful. "Who Knew" entered the
UK Singles Chart at nineteen in early June 2006 and ascended to a peak at five the following week. It is her joint fifth highest charting single in the UK and her second longest charting behind only "So What". With a total of 26 weeks inside the top 100 songs it beats her number-one hit "
Just Like a Pill". The song had success throughout other charts in Europe, where it peaked in the top twenty in Switzerland, Austria, France, Belgium, Finland and Norway, while it peaked in the top fifty in the Netherlands and Sweden. When the single was originally released in
North America, "Who Knew" was less successful. Though it peaked at number nineteen on the
BDS Airplay Chart in Canada, it was virtually ignored by American radio. In the U.S., where it was released to mainstream radio on May 8, 2006, it failed to chart on the
Billboard Hot 100, initially reaching number 18 on the
Bubbling Under Hot 100 Singles chart (which comprises the most popular songs yet to enter the Hot 100).
Billboard magazine credited the poor performance of the single on radio with significantly reducing momentum of initial sales of ''I'm Not Dead''.
Re-release In March 2007, the song was used in promotion for the
ABC television show
October Road, after which
download sales of the song increased; as a result, it debuted at number ninety-five on the Hot 100 at the end of the month. During the same period, "U + Ur Hand", the third single from ''I'm Not Dead'', had achieved major success on pop radio and was credited with "reviving" Pink's career in the US. Pink performed "Who Knew" on the May 9, 2007, episode of
American Idol. It was re-released to mainstream radio in the United States on June 26, 2007, although it had already been receiving minor airplay on
CHR/
top 40 and
hot AC/
adult top 40 stations earlier in the month. In week twenty-five of 2007, "Who Knew" re-entered the
Billboard Hot 100 at number ninety-four; it eventually climbed to number nine, giving Pink her eighth top ten single on the chart and matching the peak position of "U + Ur Hand". The song is Pink's longest chart runner on the
Billboard Hot 100, spending 36 weeks before dropping out (a feat that would later be matched by her 2013 hit, "
Just Give Me a Reason" featuring
Nate Ruess). ==Music video==