Say an American citizen buys 10 bitcoins for $300 and then two years later sells for $500 through a company like coinbase.com

Will I have to declare this as a capital gain?

How about if that person decides to give the 10 bitcoins to his girlfriend who is not a US citizen.  What happens then?

I already know about coinbase.com

Are there other very large (and hopefully safe) exchanges that I can easily buy (and store in cold storage) bitcoins with funds from a US bank account? If possible I would like to just find out the largest 2-3.

I assume that bitcoin will at some point in the near future allow side chains.  Once this happens then is it not likely that the serious new blockchain technologies will also tie themselves to the bitcoin blockchain as a way to demonstrate their validity.  

If this happens then what's likely to happen to the many non-bitchain pegged blockchain currencies that have been setting themselves up over the last few years?  For example Ethereum has sold its Ether in the start up phase and I think mining has now started.  Would the fact that a huge investment has already been made in Ether suggest that Ethereum could never be pegged to the Bitcoin Sidechain without all of the value of the purchased ether being lost?

I hope my ramblings are not too confusing.

I'm not asking this in the speculation forum as I think this has nothing to do with the current price.  Previously I posted and was asking why the price would go up when there were so many possible bitcoins and satoshis.  I had heard that with bitcoin the transit time of the currency is very low so there's not much in transit and most is in wallets.

Now when I consider my own situation I am thinking to increase the number of bitcoins I have and the reason is not for what I want to spend but just because I want to have enough bitcoin on hand.

So in my situation I expect to keep around $1000 in bitcoins on hand rather than have to go to USD every time I need to get more coins.

If we all have this $1,000 or at least some decent amount then even with 21 million bitcoins is it right to assume that the supply will be limited and this would make the price increase.

When you say deflation are you meaning that after those 21 million have been issued then slowly bitcoins will be lost and so what is left will have more value?  But does that really make the current price reasonable.  I can't understand how something that will have 21 million coins with each divisible by 1 million can have a value that is as high as near to $300.

If I take speculation completely out of the picture and buy a bitcoin for $300 today then why would (or will it) be worth more in 1 year (again from a technical only point of view).

I understand there's a lot of speculation out there but taking that out of the equation then are there technical reasons why price should rise or fall?  What I keep hearing is there's a limited supply of bitcoins. But is the supply really limited if we can have 21 million and then each of those can be divided up a million times.

Thanks for explaining about the transaction fees.  If you don't mind can you give / estimate what a transaction fee would be for an object of any size that you think would be a good example.  I would just like to get an idea of how much these fees would add up to.  Thanks

I am trying to understand what Etherum actually offers that cannot be replicated.  From what I understand the only thing may be transaction time but then can that no be handled with side chains coming from Bitcoin? As for the smart contracts, can that functionality nt be added into Bitcoin?

I watched a video and it mentioned "anything can be stored on the blockchain".  My question is if anything can be stored there then what will stop the blockchain size getting so big that nobody could store a copy of it?

I thought the key benefit that the Ethereum has over Bitcoin is smart contracts?  So if Bitcoin could have smart contracts then what would be the benefit of anyone using Ethereum over Bitcoin?

I just read a poster saying "Bitcoin is not the best technology around".  It made me wonder.  Can it be changed to be better and if so is that what is planned or is the technology so baked in that it cannot be improved upon?

I am reading a lot about side chains and other changes to Bitcoin.  Is there any place I can look that could give me some very high level ideas of what is coming up.  Maybe if there's nothing out there some of the people could help here by giving some rough time estimates.  Hoping for some good advice from the members of this community that will help me and others learn more about the future of the Bitcoin platform.