Alright, maybe I'm missing something, but I don't understand the "I made ____ in ___ hours/days" posts. I am completely behind the "Look at this site I made", but the "in X hours" part confuses me.
1) Persistance is one of the most important traits for an entrepreneur. We're in an ADD society, and things do not happen overnight. It's easy to throw together a website, but it's more difficult to stick with it, refine it, get people using it, and most importantly, get them paying for it. These posts often strike me as demonstrating ADD, moreso than anything else.
2) It feels like misplaced gloating. I think it's great that you're smart, entrepreneurial, and able to create prototypes quickly. But it's really not worth gloating about how fast you can put up a prototype, most people on this message board could do the same if they weren't working on their real ventures. If you absolutely insist on gloating, it would be better to do so about how many millions of users you have, how many millions of dollars you made, or how many days you were able spent on a beach last year. If your weekend project can achieve high marks in any of those categories, then I'd definitely want to hear about it.
3) Is it an attempt to demonstrate intelligence/ability? In today's programming landscape, there are so many automated libraries and frameworks that it's pretty easy to put almost anything together (want to put up a site that links satellite images, recent macroeconomic trends, and real time XYZ events, no problem). Combining some subset of available frameworks and libraries doesn't demonstrate intelligence or ability, even if you can do it in a weekend.
4) If it is really that brilliant of an idea, don't rush it. Go in stealth most for at least an additional weekend, and thoroughly plot out how you'll turn this into a feasible product.
5) Is it an attempt to demonstrate how entrepreneurial you are? A better way to do that would be to pick one random idea, have the confidence that it's so good that you are willing to commit yourself to it 100%, pursue it regardless of what other people are telling you, and make it work.
6) Is it an attempt to get into YC? If this works, then maybe I'd understand it more. There seems to have been more of these over the past few weeks, so maybe that's what's going on. Although, it seems to me to make you appear more ADD than entrepreneurial.
I'm completely behind your entrepreneurial aspirations, but I'd rather you really commit yourself to something, work out the kinks, get users using it, then post "Look at my startup". Then I can have faith that you've really thought it through, and it's more worth HN's time to really understand what it is you're trying to do so that we can make some valuable recommendations or questions.
The spirit of the "__ in __ hours" posts is exactly the same. Developing the barebones of a product is infinitely quicker and simpler than most people believe. Many great businesses are trapped in people's daydreams because they just haven't overcome inertia and procrastination.
I would expect that most of us here follow the logic of agile, MVPs, iterative development and so on, so why do so few of us actually make a go of it? Look at Patrick of Bingo Card Creator - he's built a small and simple product in his spare time that has grown into something that he can quit his day job for. Any one of us could have built a working prototype of Bingo Card Creator in a couple of days, but Patrick did and we didn't. Too many of us understand intellectually that we just need to launch a piece of crap and start iterating, but not nearly enough of us have the guts to follow it through. It was easy, it was cheap, go and do it.