Only if you've got a really old printer. Remember, DOS predates abstraction layers and clean printer APIs. You print from DOS by opening the serial or parallel port and sending some data over it. If you've got a DOS program that can print to PostScript printers, then you're better off printing to a file from DOSBox and then printing the result from the host OS.
That said, there's little reason to use most DOS business applications these days. There are typically open source alternatives that are far better as they aren't written with such tight resource constraints in mind and can reuse GUI toolkits and so on (again, remember that DOS programs had to come with their own embedded GUI system and for most of them 4MB of RAM was a lot - a modern program can use more than that for the window buffer). I still occasionally fire up the Psion Series 3A emulator in DOSBox (if you tweak it a bit, it will run at 640x480) and use the spreadsheet though, because I've not found another one that's as easy to use with just a keyboard and constantly moving my hand from keyboard to mouse becomes annoying.
Part of the reason for Orkut's decline in the US was that it was overrun by Portuguese speakers (mostly Brazilian) who posted (in Portuguese) in every English-language discussion, making the system unusable by anyone who didn't speak Portuguese. For the same reason, it remained popular where Portuguese was the national language or commonly spoken.
Anyway, you've got to love the message from Google: Use social networks, you're giving a third party the ability to kill your online presence and the identity that you use for communicating with your friends on a whim!
First, no it's not, nice try.
At the very least, the majority of advertising is aiming to make people buy things that they don't need. Beyond that, it's often stuff that's unhealthy or inferior to alternatives available at a lower price.
Second, people are aware that it is marketing/advertising
No they're not. For example, count the number of adverts that you're aware of in a film some time. Then look up how many careful product placements there are. See also, paid product reviews, social network endorsements, and so on. Most people are aware of a small fraction of the marketing targeted at them.
That depends on the volatility. If the price of bitcoin today is $600, but judging by previous trends, might swing to $200 tomorrow, then I'd probably just take the money. If it were a really sound choice, then my friend would be an idiot to offer it: he'd just sell the bitcoin, give me the $400, and pocket the $200. Volatility in a market is generally related to the ratio of speculators (people who just buy and sell the commodity but neither produce nor consume it) to producers and consumers. You need some speculators to provide liquidity (when you produce something, it's good if you can find a buyer now, even if no one wants it yet and it's someone who's just buying it in the hope that they can sell it later), but if their trades start to dominate the market then you get lots of volatility.
The volatility of bitcoin has dropped off a bit recently, but it wasn't long ago that it was considered stable if it only had 25% swings in the value over the course of a day. That is the last thing that you want form a currency. If someone pays me a token in exchange for some work, then I hope to be able to exchange that token for something of approximately equal value when I need to. A small amount of inflation is fine (you don't want people hoarding the tokens, you want an incentive for people with spare capital to invest it in real things), but it should be predictable.