Thinking big seems to be the favourite pastime and recommendation based on hindsight bias of people who have already made it. It's not the reason why projects are successful and it's very likely not something that will get you taken seriously by a VC investor or startup angel (too much delusion of grandeur does not befit people who don't even have a working prototype).
It's much more important to try to solve real problems (that hopefully affect many people). If your solution a) works and b) turns out to scale to something huge, then you've made it. If it doesn't scale, you might still end up with a successful und useful, albeit smaller company. Would that be such a bad outcome?
Take a look at this very early interview with him: http://www.youtube.com/watch?v=aQ5otpv6kTw
Skip to 3:57, he is saying "doesn't have to be more" after being at 29 schools. He is worried about quality over quantity. If Facebook started with this mentality and landed a billion users, why anyone would think that think big has any relation with becoming big?
As you probably already know, the situation I describe actually happened; there was one social network that grew incrementally while another opened its doors to the world. Fast forward five years and things haven't turned out the way young Boz might have expected. As it turns out, the path Facebook took to connecting everyone in the world was not the shortest and that has made all the difference. By starting small and expanding outward we built a community. By integrating networks that had originally been separate we had to focus on privacy. By throwing open the floodgates of growth in increments rather than all at once we were able to focus on keeping a consistent design and building scalable infrastructure. These things are now part of the DNA of our company and they affect everything we build." - Boz
There's usually a misconception between size and importance as well.
I agree with you that you should try to solve real problems. However, big thinking is already leaking into your advice with your parenthetical that hopefully affect many people.
There is no reason to hope. Instead you can choose an area that you are passionate about, where you can solve real problems AND that is in a big market or could create one (thinking big). I try to answer this in Why you should choose an ambitious startup idea: http://www.gabrielweinberg.com/blog/2012/03/why-you-should-c...
I often "think big" but target a specific, ready to pivot to a new specific while retaining the same architecture and philosophy.
It looks like half of you define it as "think of a problem lots of people have" and the other camp defines it as "think of a big idea" (i.e. "Lets get the human race to mars" or "I'll build a social network for the whole planet to do all of this stuff on).
The people who oppose "thinking big" see it as thinking of big problems that require impossible to complete (with a small group, small budget, and reasonable amount of time) solutions. The people who are for "thinking big" seem to be defining it as thinking of problems with solutions that will impact a large amount of people, regardless of the size of the solution required.
Sit down and try to write the Great American Novel and you're pretty much screwed. Try to write the truest thing you know, though, and there's a chance that people will pick it up and share it.
The problem when trying to solve a pain for many many people, whether you're a writer or an entrepreneur, is that it's hard to start big and good. You can start small and good, and grow big, or start big and not-so-good, and try to get good. There are many instances of the former, almost no examples of the latter.
I suppose "thinking big" really means "always be open to the idea of scaling up", or "pick markets/conditions that allow for scaling up". But you almost always have to start small to do something really, really well.
For those of you who are interested in such opportunities, http://www.reddit.com/r/realproblemsolvers is a new community for sharing and discussing such problems and solutions. please join and participate and help us create a strong community that will help solve real problems.
(1) Risk of time (and other things, including money) => go safe.
(2) Risk of money (only) => go big.
I am genuinely not sure[1], but it does occur to me that this could be the underlying difference in approach between an investor and a founder (more specifically: a founder still looking for his safety net.)
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[1] To tell you the truth, I find myself leaning towards "going big" of late. But until I found something tangible, it's just an exercise in vanity.
It could be argued that only two tech companies actually changed the world since 1980: Microsoft and Google. Amazon, maybe.
But for example, I don't think Apple, Sun, Oracle, Yahoo, Facebook, Twitter... "changed the world". They are very big, wildly successful companies, they make products and software that people enjoy (me included), but they didn't turn the world into a different place than it was before.
1) We're going to build the next Facebook! 2) We're going to found the next Apple! 3) Our product will create sweeping political change! This will produce a major economic revolution in at least one country! (Seasteading would be change on this level if it worked; creating a new country successfully is around the same level of change as this.) 4) Our product is the next nuclear weapon. You wouldn't want that in the wrong hands, would you? 5) This is going to be the equivalent of the invention of electricity if it works out. 6) We're going to make an IQ-enhancing drug and produce basic change in the human condition. 7) We're going to build serious Drexler-class molecular nanotechnology. 8) We're going to upload a human brain into a computer. 9) We're going to build a recursively self-improving Artificial Intelligence. 10) We think we've figured out how to hack into the computer our universe is running on
Likewise, when a billion people are using the iPhone to call their loved ones, that's changing the world. I mean, that's as good as it's gonna get, short of inventing the cure to cancer, or blowing the Earth up.
This is the point where I suggest the iPhone didn't REALLY change that much for most of us. Sure, it's easier to get maps and directions now (though old Blackberrys had that too). But the massively world changing innovations of smartphones are really minor conveniences wrapped in nice packaging.
Unless, of course, you live in less-developed countries, where a smart-phone may be your first computer, or even your first phone, and offers a connection to information and the rest of the world that you didn't have before.
For me it was when my parents (without any prompts from myself) got an iPhone and started emailing / Facetiming me from it.
If you had told me 6 years ago that my parents would be able to send me email from their phone, or be sophisticated enough to look up movie times while I'm out having dinner with them I would have laughed.
I think what the iPhone did was make it easy for everyday people to use technology that was only available to a select few. Not just with their technology (which made it easy to use) but also their advertising / marketing which made everyone aware of it.
When we just had dumb-phones, we were "always available", but now we're "always connected".
They might be "thinking big", but they're also "working small". They have to.
Can you imagine someone coming up to you in a Twitterless world and saying "Hey, do you want to invest $10k into my startup that allows people to communicate with each other in 140 characters or less, in an online open forum?"
Startups are a high risk endeavour. There are much better odds in having a small success than a large one.