Despite some sniping, I think that HMRC can claim a pretty resounding victory with online Self Assessment this year. Their figures say a little under 6 million people sent their tax returns in via the website. That's about 2/3 of the total possible, maybe even 75-80% if you count only those who actually send their tax return (figures vary but there is quite some number who don't send a tax return at all). Perhaps most impressive is the growth rate - over 50% up on last year.
Next year, the online service will be 10 years old - I worked on the team that put it live in April 2000. I didn't think it would take this long for it to get 70% takeup, but I'm delighted it's there now. Plenty of other services with some catching up to do of course.