What is it about online tax systems that makes them creaky. No sooner have we got past the problems in the UK and all of a sudden, we find it’s contagious. Yesterday the Australian Tax Office had some volume related problems – with 20,000 users trying to send their returns – and the system failed. That said, this year more than 500,000 people have sent tax returns in via the ‘net (about 25% of the total). Building systems to cope for peaks in demand while leaving capacity idle for the rest of the year is not a fun game. The two key things to do are to fully stress the system and build time to see what the breakpoints are; and to build a system that does several things so that usage is broadly even, making for less capacity wasted. This latter point is why we built the Government Gateway – we knew that personal tax would be annual, payroll tax would be monthly, VAT quarterly, student loans annual (But not the same time as personal tax) and other services (like Child Benefit) would be more ad-hoc. Overall, we thought that there would be a continuously moderate to high load with occasional peaks, but not huge jumps in volume. We’re not there yet, but we will be.