Online Business Tax Id

Do you need a tax identification number for an online business?
I told you only need a number Tax ID if you work hard for you to have (employees), but I intend to do everything by myself, although for to do business with my mother (she invests and assess and I do all the world, and to assess.) Also I was told that the identification number Tax is only necessary if your doing local business, as in a specific location.
http://www.irs.gov/businesses/small/article/0,, id = 97872.00. html You are probably OK, unless you sell tobacco or gas or something that has an excise tax. You must use your own personal number social security in all forms, it looks like a sole proprietorship.
File a DBA Online – Get a Federal Tax ID or EIN Number
