Irc is easy. It does not require huge knowledge. If you can't login to irc channel, even by simply typing "web irc client" in google and clicking on the first link, you are not a technical person.
That makes little sense to me, if the point was to use the applicants ability lean how to use a new technology as a screening filter then I don't see how using irc fits that requirement.
Although I'm opposed to the idea of using irc as a screen, since I know that there are people who don't use it but are technical, I'm not suggesting that most technical people don't know what irc is. Just that it's kind of useless to use a known technology to test the ability to learn new technology, especially amongst developers.
But what if you're, as the article says, used to skype?
would it occur to you that there might be web based irc? Skype doesn't support that, and certainly the only things you see when you google 'irc' are clients you'd have to install, or worse: compile. Tough freenode does seem to have the webclient high in the list of results...
But then looking at their client is another example of why irc might not be straight-forward enough to use. This is what happened when I tried to use it with a random, but obviously too short, user name:
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[19:43] Licensed under the GNU General Public License, Version 2.
[19:43] == * (qwebirc) Looking up your hostname...
[19:43] == * (qwebirc) Found your hostname.
[19:43] == Connected to server.
[19:43] -herbert.freenode.net- * Looking up your hostname...
[19:43] -herbert.freenode.net- * Checking Ident
[19:43] -herbert.freenode.net- * No Ident response
[19:43] -herbert.freenode.net- * Couldn't look up your hostname
[19:43] == CGI:IRC host/IP set to gateway/web/freenode/session ...
[19:43] == bob Nick/channel is temporarily unavailable
[19:44] == Disconnected from server: Connection to IRC server lost.
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Riiigiht, very usefull, I can't use the nick bob. What now? How do I change it? where's my change button? etc. etc.
I think my point stands, irc might not be 'hard' but for a first time user it's not easy either.