...whether a dictionary can usefully be run by chat and semi-consensus; and whether it's right for readers to "select" a meaning they find "relevant", rather than one that's actually correct.
The idea behind Wordia is explained in the article:
The everyone-join-in dictionary is called wordia.com, and is the joint offspring of the television producer Edward Baker and Michael Birch, the internet entrepreneur who founded Bebo, the social-networking site. They've linked up with HarperCollins, the blue-chip publisher owned by Rupert Murdoch, to make use of their electronic dictionary of 76,000 headwords and 120,000 definitions. But the unique selling proposition behind wordia.com is visual: they want to compile an archive of videos in which thousands of members of the public will offer their own definitions of favourite words and have them posted on YouTube, with which Baker and Birch are also in partnership.
But, as Walsh points out, dictionary definitions aren't decided upon by random celebrities; they're decided upon by qualified language experts who know something about the language and where the actual words derive from. That's not to say that we can't have our own ideas about what certain words mean to us - they're more the connotations of words than their denotations - but that if we don't have accepted and agreed definitions to words we'll be left floundering in a sea of vagueness and, like...whatever.
The other point is that dictionaries do respond to new words and new meanings, but they're a bit more careful to source these than Wordia. Look here and here for more details about what lexicographers actually do.
But Walsh is not entirely negative about different approaches to dictionary compilation. He speaks more approvingly of Urban Dictionary, which collects different meanings from its contributors and is well known for its up to date slang definitions (and its rude words and thinly veiled personal insults e.g. "definition of gay = my stupid English teacher").
And if you think that's sad, have a read about this chap who has just read the OED from cover to cover.
ENA5 - Language Change
ENGA3 - Language Explorations