He has famously said: "I don't invest in things I don't understand."
On that basis you can be pretty sure Buffett isn't one of the mega-wealthy US investors who have been buying into kiwi tech stocks, pushing them up into price territory that has the market debating whether we are at risk of a bubble.
I wrote about Xero's market rise just six weeks ago after it had surged through the $1 billion market capitalisation mark and rapidly on to $1.3 billion.
Last week its value spiked as high as $1.71 billion before tumbling sharply back to end the week at $1.55 billion. It has been highly volatile on relatively thin trading - almost the opposite of the business itself, which trucks along steadily setting and hitting solid growth targets.
Something is up. Probably more US investors catching up with the buzz that Xero's cloud accounting system might be the next big thing. But not Buffett. And it's not a real tech bubble either, certainly not in the 1999-2000 sense of the word.
Back in those bad old days companies weren't even being valued on revenue, let alone profit.
It seems naive now but Wall Street was valuing stocks like World.com and Boo.com based on clicks and users with little thought to how they would be monetised.
It was an old-school gold rush, the market believed the first players in to stake their claims would dominate the new market. But unlike the gold fields, real estate online is infinite. Customers are fickle and switching loyalty is easy.
New improved products with better customer experience can quickly knock incumbents off their spot at the top.
The companies at the centre of the NZX tech bubble talk - Xero and Diligent - are smarter than that.
They are part of a generation of online service providers that gets the new model. And they have revenue streams. So for them to be tarred with the tech bubble label would be unfair.
Diligent, which gets less press than Xero, is more niche-oriented but still has the potential to be a big player in a lucrative and large global market. It offers an online service for company directors.
All the boardroom paperwork can get done in one system easily accessed anywhere in the world in a uniform manner which allows board members to share information and keep up with the accounts and reports they have to read.
Like Xero it is growing fast and creating a buzz in the US.
Diligent last month reported revenue for the first quarter of 2013 at $17.5 million, an increase of 84 per cent compared to the first quarter of 2012.
That annualises to revenue of about $70 million a year, not bad, but its present market value of $582 million puts it ahead of companies like Michael Hill, which has operating revenue in excess of $500 million a year (not to mention profits and dividends).
The extra market value is all in the expectation of future growth. Which means you are taking a punt no matter how educated a punt that might be.
Cloud computing is the future of commerce but picking which companies will triumph, or even last long enough to return dividends is notoriously difficult.
There have been some spectacular failures even post the tech bubble.
MySpace - the social media site - was so hot Rupert Murdoch paid US$580 million ($680 million) for it in 2005. It was still running so hot that Murdoch has since admitted he blew it.
He could have sold it for 10 times that price just a month later, he told his shareholders in 2011. But social media users opted for Facebook and Twitter.
Murdoch ended up selling out for just US$35 million in 2011. Based on its performance since then, he was lucky to get that.
In the digital age established technology can become outmoded faster than even the most agile companies can change gears.
The consumer shift to smart phones has been a real blow for phone maker Nokia and the Apple iPhone nearly killed Blackberry. Right now a buzz topic for tech writers is the death of the PC or personal computer.
Not a personal computer in the sense that a phone is now a personal computer, but PC as the industry term for that box that's been on your desk with a screen and keyboard for the past 20 or 30 years.
Last month Bloomberg reported that "personal-computer shipments plummeted in every region of the world in the first quarter as buyers opted for smart phones and tablet computers".
PC shipments fell 14 per cent in the first quarter - the worst such decline on record - to 76.3 million. That kind of slump makes the future of the traditional PC seem quite precarious even compared to such old-world communication technology as, say, a newspaper.
Who knows how long the print and paper edition of news has left but its demise has been widely predicted now for more than 20 years and the rate of decline has stabilised to the point that savvy old Buffett has been buying newspapers big-time.
His investment firm Berkshire Hathaway has snapped up 28 daily newspapers in the past 15 months, paying a total of US$344 million.
Buffett doesn't dispute the decline of print but he has seen that the relentless future focus of the market has left US newspapers cheap and unwanted with plenty of value still left on the table.
Buffett believes there will always be demand for local news and he is betting that fundamental proposition combined with a cheap entry point will see his investments deliver good steady profits.
It is literally the opposite of the dot.com model, which puts all the value in future earnings and largely ignores the quarterly cashflows.
Buffett is famous as counter cyclical investor. And he is famous because it has worked for him.
By logging on to Twitter he has reminded us that he is anything but bull-headed in his attitudes. If something works he'll use it.
But just because it works, even if it works very well indeed, doesn't make it a great investment.
