With what kind of profits would you recommend forming an LLC?
Actually, it is not the determination of profits, it is how to minimize you taxes and maximize your expenses. If you want to run your domain as a business, forming a LLC is a good idea. Consult your accountant to discuss it. You can even do a Sub-S and form a corporation. Some states it is real easy to do.
For the most part, how much do you plan on spending for the domain business? (reg fees, drops, promotion, subscription fees, hosting, hardware, software, internet.. could all be expenses of your company. You just need to mkae a profit a some time (and profit is more revenue than expenses, there is no level. My profits are only 400-500 each year, but teh expenses I claims and salary I take offset any profit)