And contrary to what Rob posted I do not see any references to asking prices, only finalised sales.
The cryp.to domain has been online for as far back as 1997(!) and was registered by a German cryptographer. It’s for sale for $1 million for those interested (I asked).
Don't get me wrong - the article is well written. However the values talked about come from the developments. I don't think it's wise for new entrants to be sinking a lot of money into the domains for speculation and I see these kind of articles as a way to attempt to hype things beyond reality. 'Hey Rick Schwartz paid $500k for flowers.mobi.... this will destroy .com....what's that? You went broke buying them all?....ah well'
Only .am really made it big from the .am / .fm duo with the sale of the single character domains 9.am for a record $169,000 seconded by 6.am for $45,000
This is not 'making it big' in my view and *could* cause people to wrongly believe it is worth spending their money on other am/fm domains which they are 99.99% guaranteed not to sell.
When it comes to development - sure use whatever extension you want. Ultimately it won't matter although you will be hindering yourself with mistaken urls and search engine presence.
IF however you want to buy and sell domains undeveloped, as most people here do, then investing lots in alternative extensions is not the way to go in my opinion... and to some extent that is borne out in the daily sales and market movement. I definitely don't see how alternative domains are 'disrupting' .com though and that's what the title of the article was.