This is why there needs to be applications and apps that makes using BTC more user friendly and more "idiot proof"; I have not been able to use circle yet, but I would expect that this would be one example of how using bitcoin can be like this.

I think an offer for a 50% discount would likely be some kind of a scam because the costs associated with accepting other types of payments are not going to be that big, especially with selling a bike. The amount of the discount should always be less expensive then accepting non-BTC payments as the consumer and the merchant would share the cost savings.

I think this would really amount to paying others to mine their altcoin by buying the coins miners mine back from the miners at a fixed rate. Once the fund to buy the coins back is dried up the miners would no longer have an incentive to mine and since you were the only buyer the price of the coin would drop to near zero (or more likely to zero).

This is exactly the right answer. The small incremental increases in adoption will have a small effect on the price of BTC however once enough people use bitcoin that businesses can pay their suppliers and vendors in bitcoin the price will be much higher as there will be much more demand for bitcoin.

It is not possible to force someone to use bitcoin. Once you control an address, no one can force you to sign a TX that spends your coins.

There are some situations when it is not in a person's best interest to you bitcoin. One example of this would be a title company or a law firm account that is holding funds on behalf of their clients. Both of these types of companies need to have a very clear paper trail documenting every single transaction into and out of their bank accounts.

Use Bitpay. There was a recent transaction involving a piece of land in Lake Tahoe that was purchased with bitcoin that was processed with Bitpay. I think there were a couple others as well that were processed in a similar fashion.

You would still have 5th amendment issues in this case as if there was incriminating evidence against you on there, you would be forced to provide evidence against yourself.

If you use cash to buy things like food, then you would not need to spend the "income" money that you earn to buy food so you could use that money to buy other things. Remember that money is fungible so it doesn't matter which dollar you use to buy something as long as you use a dollar.

As said above since the fee is so small presently for most transactions the merchant should just absorb the TX fee as a cost of doing business. This would likely be less then accepting any other form of payment.

How would he reap the rewards if he does not spend any of his BTC? He would not have any other way to profit from BTC without actually selling/spending his BTC.

I agree with this. There are too many risks with accepting SMS for payment for BTC. Unlike with a credit card payment it would be very difficult to verify that a SMS payment was authorized by the account owner as the person who setup the SMS payment would likely be in possession of the phone.

Even a 5% or a 6% hashrate is pretty small. The fact that they are essentially solo mining likely means that they wish to remain anon and value their privacy. I would say that they are likely mining for financial reasons as opposed to an interest in BTC or wanting to help the network. Looking at the address history I do see some inputs that are from the ghash mining address so it is possible that they are mining on ghash as well. The OP could contact ghash to see if they can try to get contact info for the address, but I think that would be a long shot at best as ghash also values privacy.

When these types of addresses are used the coins are often transferred to another address that has never been used before, and will only be used once. I think the average user that has been using bitcoin for several years will have used several hundred if not thousand addresses.

The article said multiple times that the price was "well worth it" and that they were happy to only receive 60% and 80% of their sales.

The CIA is very capable of creating things. I think they would be capable of doing so, but as I said above they would have very little to gain from it. It was said above that they would use the hashpower to steal passwords, but the CIA has much easier ways to steal passwords. They are also not in need of needing "free" hashpower as they will get more or less as big of a budget as they need.

This is not a single city lol. I agree with the above post that says it will likely be a city in the netherlands. They have a small amount of regulation and low tax rates.

Why wouldn't you spend your BTC, then buy an equal amount of BTC on an exchange and/or on a trade? This would increase the amount of BTC adoption, will likely allow you to buy goods at a discount and increase the size of the bitcoin economy.

This would make sense except that SHA-256 is not very good for keeping what you are saying secret, but rather to ensure that what is said was in fact said by a certain person. If the another country used this type of encryption then it would be very easy to tell what is being said.

A quantum computer is not necessary for this to happen. The fact that the difficulty is increasing at a rapid rate means that, on average blocks are found less then every 10 minutes. The answer to your question is "yes" the 21 million BTC will be made faster, but this will not be because of quantum computers, it will be because of ASICs.