The Revenue start to send out letters and SMS messages to people to tell them how they can get hold of their draft tax statement. The draft tells you what the tax people think you've paid, what you should have paid and how much they owe you or you owe them.
The draft is available online. I heard on the radio that the website had collapsed under the strain of the thousands of people trying to check. A couple of hours later I was trying to get on the website to have a look myself. The particular pages had a message along the lines of "We're a bit pushed at the moment, please try again in an hour or so." It's about eight hours later now, around midnight. The website has the same message. Down for the majority of the working day then.
Apparently the system was designed to deal with 100 transactions per second, clicking on a link for instance being a transaction. They had something like 5,600 transactions per second at one point which is why the system gave up the ghost. Whilst that sounds like a lot they've only had about 100,000 people trying to have a look and, though I'm no web designer, that doesn't sound like much traffic to me for a country with 22 million tax payers.
Spanish websites have improved massively in the time we've been here but they can still be pathetic. I wanted to check my mobile phone bill a couple of weeks ago. The pages I needed were down for five days.