Problems with the article
Apparently this is a very loose term used to distinguish people who have acquired some kind of long term fame or notoriety associated with popular culture.  Hendrix, The Beatles, Elvis, Sinatra, Crosby, Jolson, and so on might be described as "pop icons" because they are strongly associated with, and in some ways personify, the zeitgeist or an era in popular culture.  This includes film and other popular art forms, and sport (De Niro, Monroe, Bogart, Muhammad Ali, Pelé).   It often includes people who died relatively young (Morrison, Hendrix, James Dean).  So far so good.

Then there are people whose work wasn't primarily in or related to popular culture, but whose image has been co-opted as a pop icon (Einstein).  Well, okay.

Now looking at the article, we see a section called "Notable pop icons" comprising, presently, some forty names.  More than half of those names are sourced from a single news story based on a press release produced by a single media organisation in November, 2003. A further seven of them are base on a similar news story from a different media organisation in 2005  The criterion for the list of 100 members given in the first news story, it turns out, is a viewer's poll by a single cable television channel, VH1, from a shortlist drawn up by "A panel of celebrities and experts – including presenter June Sarpong, newsreader Krishnan Guru-Murthy and GQ editor Dylan Jones."  Presumably the experts on the panel asked to remain anonymous.

Further examination of that single source also demonstrates that there are unexplained omissions from our list.  If we assume for the moment that membership of the VH1 list (which is biased towards the tastes and cultural memory of the British viewership of that channel) is a sign of "pop icon" status, where is Princess Diana on our list?  She's number 5 on the VH1 list but completely absent from ours.  Similarly, The Simpsons (VH1: number 6) and Robbie Williams (VH1: number 9) are omitted from our list.

Looking in the opposite direction, Aerosmith is included in our list because MTV  featured the band in a program called "MTV icons", but is nowhere to be seen in the VH1 100 (not surprising as the band, while not unknown in VH1's target market, isn't exactly a household name).  And while VH1 lists first man on the moon Neil Armstrong at 76, his trumpet-playing namesake Louis Armstrong (selected as one of 100 "Icons of the Century" by Variety) is nowhere to be seen on VH1's chart.

There are also problems with the membership criteria of the sources.  I've already mentioned the UK bias of the VH1 list (which goes some way to explain the presence of Beckham and Robbie Williams, both household names in the UK but not so well known elsewhere). The Variety list, for  instance, sought to represent "every side of show business", so relatively obscure figures such as Arthur Freed (who wrote the lyrics for Singin' in the Rain and produced many hit films) are listed as "Icons of the Century".  Clearly the people on the list are there because they're "iconic" in some sense, but not in the sense implied by this article.

Another thing that isn't addressed is the requirement of longevity.  Can we include Britney Spears, who a mere decade ago was an unknown with a recording contract and an audacious concept for a pop video for her debut single? Britney Spears' career has hit an air pocket, and there's no way of knowing whether her image will recover in the public mind.  Perhaps it's premature to describe this relative newcomer as a "pop icon".