Is it your business to buy/sell bitcoins? If so, then you should be registered with FinCEN regardless of the transaction amounts. Also, in that case, for certain high-level thresholds you should be collecting ID according to their guidelines and reporting them...depending on how many "several thousand" is, it may qualify as suspicious activity..
You also should be tracking profits to report on your taxes.
I'm following all tax laws. I sell for cash and rebuy, so it does not qualify as investment activity. I understand this means I would need to register for large amounts, but I was under the impression that there was a threshold under which you were exempt from the regulations. I'm trying to understand what that threshold is. I just do this a couple times a month as a hobby to help spread bitcoin.
If you are right that there is no threshold then everybody who helps their friend buy in is in violation. I really hope I have an option between stopping what I've been doing and registering. Can I even register as an individual, or would I need to start a business first?