today's educational tidbit: "Employer ID Numbers" An Employer Identification Number (#EIN) is also known as a Federal Tax Identification Number, and is used to identify a #BusinessEntity. Generally, businesses need an EIN. You may apply for an EIN in various ways, and now you may #apply #online. This is a #free service offered by the Internal Revenue Service (#IRS). You must check with your state to make sure you need a state number or charter.