1) You mention of the last 8 blocks, one is near full with 1.8 kb left. You suggest this could allow 9 more transactions? So theoretically, you are saying, if the usage of bitcoin had increased, and 10 more people, tried to send a transaction during this time period, the block would have been full and those transactions would not have been included? Is this accurate? Since very few people use bitcoin, it seems self-evident, that if adoption increases, the likelihood of full blocks increase. Is this correct?
No, not even close. If you have been using bitcoin for more than a day, you should know there are two concepts called "fee" and "priority". If ten more people had sent transactions at the same time, and they included a fee at all, or the input utxos had any confirmations at all, the transactions would be included. I send many of my transactions with a very low or zero fee to mark them as
low priority, can wait if the block is full. They almost never have to wait.
2) You then mention there are dust transactions, outputs which cost more in fees to spend, than the value of the output. If I'm sending a bitcoin from A to B, would this be considered a dust transaction?
You obviously don't know what dust is, and I doubt you know how transactions are constructed.
A transaction has inputs and outputs. Each input is a reference to an earlier transaction output by txid and number of an outoput in the given txid. When an input is spent, the entire input is spent. When all outputs from a txid have been spent, the txid can be pruned from the utxo set (which is good).
A dust output is an output of just a few satoshis. So small that including it in a transaction would increase the necessary fee for the transaction more than the value of the input. I.e. it will never be possible to spend economically, and litter the utxo space forever. No matter how many such inputs you have, the combined value of them is negative. Those utxos are called dust. We don't want transactions containing dust outputs, because those will litter the utxo set, which is kept in memory on all nodes, forever.
Was that clear? Faster increasing UTXO set is Gavin's main argument against a block size increase, btw. Dust is the worst, since it is economically unspendable, and will stay there forever.
There isn't much included, correct? Assuming this is the case, since I'm moving a fair amount of money, wouldn't it be safe to say that I would want to ensure that this transaction takes places and increase the fee? Forgive my ignorance with this regard. Or would it only be spam if I was for example sending .00099 btc and I had a fee of .001 btc to ensure that the transaction was hopefully included in a recent block? Perhaps a better exampled would be, me needing to send btc to my brother in Germany. I want to make sure he gets it, that the transaction is included, so say I send .05 with a fee of .05 or a permutation of that with .049 and .05 or .05 and .049.
0.00099 is far above the dust threshold. It is 513 satoshis or thereabouts. The monetary value, even assuming 0 txfee, is much less than one cent.
3) How would this(the above mentioned) be considered abuse? In either of the above mentioned transactions I need to get him ~$20USD for whatever reason I have. This seems like legitimate usage, no? How is the determination made whether usage is an abuse or not?
I have no idea why anyone would consider what you explain there abuse.
