[tomcorrigan]

It depends where you look for the common meaning. To native English speakers in the UK, Australia, New Zealand (ie outside North America, coincidentally including the country where the English language developed) specious has one very clear meaning

I would also direct you to the usage examples in your link. All of which use specious in a context that implies deception of outright falsity. I have never ever seen specious used synonymously with obsolescence.

[svachalek]

I read that as "showy (obsolete)". Either way, amalag's says "wrong", the other says "deceptive" and "false", I'm not sure what anyone's arguing about. Specious data has no value.

[victorh]

I disagree with your argument! If inventing the language meant you got to choose all the definitions we wouldn't have English in the first place. Shift happens. I don't think this particular usage is common, though.