rKVTLpJXNvUNsUKgAHy1v1HbLArwtmiaaZ

Maybe it can be good advertising for the currency, but maybe also that the if the same CPU cycles were used in the mining process the currency can be perceived stronger because of the bigger CPU backing... Who knows which is better?

Maybe the rule is "less than 999 $"...
Have you tried with a sum lower than 999$ yet?

Reading the chart, I see Bitcoin in the "Stealth Phase".
I don't think institutional investors are trading bitcoins, which is also unknown to the public.

I'm also noticing the updating of bitcoin-qt it's very slow.
What is the bottleneck here? My CPU is used only at 30% during the process, I've 2GB of RAM not used and the downloading of the blocks is at a rate of 500kB/s (the bandwidth for a normal download is usually 7MB/s).

Is the speed of the initial bootstrap limited by my hard disk drive read/write performance?

The transaction arrived correctly and was included in the block 229321, as your links says.
What didn't arrive? If your local client is not updating the balance, one of these thing could has happened:
- Your address is not 1HEwRtfwCiebVxGP2HsffxKexF3HGdong8
- The client doesn't have the block 229321 (mabe it's disconnected from the network), so it can't find the transaction

The physical keys you're referring to are the private keys (i.e. 256-bit numbers) of your addresses. Of course you can write them down (or memorize if you have a good memory). See https://en.bitcoin.it/wiki/Private_key