When your business starts generating revenue, you need to begin paying quarterly taxes.  The IRS doesn't exactly appreciate you sitting on your owed money all year waiting for tax time.  They're due every 3 months, starting on January 15th.

If you either didn't pay taxes last year or have already have enough money withheld on a W2 to cover last year's taxes, you can skip the quarterlies.

As a new taxpayer, mine may be optional, but I wanted to get into good financial habits and pay them now anyway.  I went onto the IRS's online payment system and added myself to their database, including my name, Social, and checking account information.  Like many user registration forms, they send you a confirmation mail that you must use to activate your account.  The difference is that the IRS USES THE REAL MAIL.  What should have taken under 15 minutes to process instead takes fifteen days.  If my taxes were actually due today, I would have been screwed.

At the IRS, they know it's a new year - they just don't know what decade.