Yeah not sure about this one. I'd been TinyPNG'ing my textures for about a year now, their algorithm just got 5-10% better a few months ago. But for android or ios builds for example, it's tricky.
Try unzipping the build though. An android APK file is actually just a zip file as far as I can remember. You might be able to go in, compress the images, and zip it back up. It's probable they hash the package though and it'd produce a different hash so it might fail. But give it a shot.
It's a bit of a shame as there's quite a few open-source compression algorithms out there. It should be a pretty trivial thing.
In any case, you may find comfort in the fact file sizes don't really matter all that much for native apps. 20mb or 50mb, I doubt it makes any difference to users, as it's a one-time download and most users can easily hit 50mb in a minute of downloading. And in terms of memory or performance, there obviously is no difference at all. Perhaps it's a better idea to lobby for improving the 50mb limit, which was raised to a few gigabyte but only through so called expansion files. Look into this if you have time, perhaps YYG can accommodate you better here.
How are they defining "spent"? Exchanged back into money, or actually used to buy products?
Good question, I wondered this myself. On the one hand, because all bitcoin transactions are public (except the off-the chain ones, of course), you can do lots of number crunching and analytics. On the other hand, because they're pseudonymous, it's still hard to track who is spending them and on what and through what client.
So, they do a few core things. Firstly, they identify addresses. For example, you can deposit money at one of 10 large exchanges and wallet services, then withdraw it. So say you deposit some bitcoin at Coinbase, then withdraw. When coinbase sends you the bitcoin, it will show the senders' address, which can then be identified as being owned by that exchange. You now know a Coinbase address. You do this quite a few times until you have a solid pool of verified addresses. When you have say 10 bitcoins in your wallet and send 5 bitcoins, you're not really sending 5 bitcoins. You actually send part of the inputs that make up the 10 bitcoin in your wallet. So say you got 10 bitcoin because you sold 1000 hamburgers at 0.01 bitcoin (~$5) each, if you want to send 5 bitcoin, you're actually sending the inputs of 500 0.01 bitcoin payments. So you can actually pretty quickly identify a large number of addresses with single transactions.
Next up is change. When you send 5 bitcoin, you might need to send the inputs of 6 bitcoins (say three inputs of 2 bitcoin is the smallest you have). What you do is actually make a transaction with two outputs, one for 5 bitcoin to the receiver, and one of 1 bitcoin back to you, that's your change. These change addresses also verifiably belong to the sender by definition of the protocol.
So it's actually possible to identify and associate a large number of addresses. We can then analyze them. How much volume is going from miners to wallets, to exchanges, to satoshi dice etc.
In any case, regardless of whether coins are just moving around, the velocity of money is important and all metrics (like the above graph, transaction volume etc) clearly point to a pretty rapid growth.
Interestingly, some of the transactions people would most love to see might end up happening off the chain. I believe Coinbase does quite a bit of off-chain work as a payment processor when Coinbase users pay Coinbase merchants. They probably internally move things around and then balance the books on the blockchain a few times a day. This means their transaction volume/fees might actually very much understate their actual impact.
The pyramid scheme analogy is ridiculous. That's like saying anyone who bought domain names in 1993 was involved in a pyramid scheme because investing into something and in return make more money if other people exercise demand for those domains is like a pyramid scheme.
Domain names have intrinsic value. Bitcoin does not. There are many people to whom the only value of a bitcoin is the chance of it becoming worth more, they intend solely to sell the bitcoins later and make a profit. People investing into bitcoin is what has caused it's value to increase.
A pyramid scheme is when the only value of your investment hinges on getting others to invest. So if everyone behaved like the individuals who invest in bitcoin solely to make profit, it would be a pyramid scheme. It's would be a strange form of pyramid scheme but it'd have all the characteristics.
I don't think anarchically-styled cryptocurrencies are going to take off, unfortunately. For a currency to be standard people need to "trust" it, and many people just aren't willing to put their faith into something with no government control. However the code behind how bitcoin works is fantastic and I can see it getting used in the future.
I'm not sure if intrinsic value is a valuable way of discussing things. It's actually quite complex and has become a very subjective term. For example, Gold is often said to have intrinsic value for two things: it's properties of beauty and industrial applications of gold. Thus we can state that before human culture arrived at notions of beauty, gold had no 'intrinsic' value. Before gold found industrial applications, it did not have intrinsic value either. More importantly, gold has traded above its industrial value since pretty much forever. Diamonds are a similar story, synthetic and natural diamonds have similar aesthetic and industrial purposes, yet natural diamonds sell at a significant premium. Oil was long held to be the worst thing ever to come across when mining for coal before it became the worlds most sought after good. Does a dollar bill have intrinsic value? Well, it's made 'legal tender' and the paper has some value, but a $100 bill trades at many orders of magnitude its paper value, other than that the dollar only has government backing which comes down to human trust & human agreements as to what has value. In all those respects, bitcoin is no different. The only difference is that Bitcoins can not be forged and bitcoins are scarce, unlike dollars which can and are being printed in copious amounts.
And bitcoin certainly has many applications. It's a bit of a technical story in the end, but the concept of bitcoin, being able to make a digital good scarce, and being able to have an unforgeable network of unlimited nodes agree to a single timestamped public ledger has tremendous value. Besides transacting value by making changes to this public ledger (bitcoin as a currency), a single bitcoin can be split into 100 million fractions (as a dollar can be split into 100 cents). These can then be used as stocks, bonds, but also smart property, contracts, proof of ownership of physical or digital goods, notary services, timestamping services etc. Even if you completely disregard being able to instantly, at virtually no cost, transfer value across the world (the currency side) and act as if it doesn't exist, bitcoin has a huge amount of value still from its applications that I just mentioned. You could build accounting services, notary services, escrow services, inheritance, smart property and proof of ownership services on top of the bitcoin protocol. Bitcoins are then essentially the individual slots on the public ledger which you deposit and sign, thereby proving e.g. ownership, a payment, timestamping a document etc. To say it has no value beyond its investment value is simply a gross lack of understanding of the full capabilities of the protocol. Bitcoin is much more than just currency. It's like saying the Internet only allows exchanging 1s and 0s, thereby allowing someone to send to every home the scores of a local football match, instead of saying it allows to exist the internet in its full glory as we're both familiar with today. Domain names are nothing compared to bitcoin in terms of intrinsic value.
I'm not sure whether they're going to take off, either. I do know that the trend is *way* up at the moment and that there's actually major interest from 'mainstream' parties. Various billion-dollar retailers accept bitcoin, there are a few million users of various popular bitcoin services (some that didn't exist 1 year ago) and they double every 4-6 months. There is major funding from venture capital investors among which marc andreessen (made the first widely used webbrowser and later founded Netscape), there are tens of thousands of merchants, growing rapidly. The media is actually getting more positive and giving it way more coverage. (it used to be Silk Road this and that, now it covers Bitcoin as if it's a Startup company reporting on the good and the bad). And various countries have called bitcoin an important innovation and are obviously unwilling to outright ban it fearing the next big tech-innovation will happen elsewhere.
Let's not forget, we have a history of trusting in things where there is limited government control. Look at the internet for example, it's largely decentralized and no government can really pull the plug, censor it or control it. Of course there are regulations, of course some content is illegal. But the internet protocol is not in any way government controlled, just like the bitcoin protocol isn't and can't be. Yet, everyone uses it. Fundamentally, bitcoin is a technological innovation that's completely agnostic to being used for any particular thing such as currency. It's just a decentralized public ledger based on the same cryptography that's securing your identity and all money transactions of any bank, all government secrets, your credit card transactions ec.
At the end of the day, businesses will build *on* the bitcoin protocol, just like they do on the internet protocol. These businesses can be held accountable, are subject to the law and regulation. People will likely find they can trust in these businesses over time, just like everyone is using email services from companies running on the internet, a decentralized unregulated technological innovation we call the internet protocol.