By recording a video and publishing it on his Twitter account, it showed 32-year-old Williams was not only tech savvy, but also media savvy - and the latter is something he hasn't always got right during what could be described as a "colourful" career.
It could be the way of the future for the game's ageing players. But who else in the All Blacks should seriously consider doing the 'Ali shuffle'?
Unlike Williams, Highlanders hooker Andrew Hore doesn't appear to have a Twitter account. He is also unlikely to shed tears at his press conference when he does finally call it quits. But, just as Williams suddenly felt the time was right to move on, surely Hore must be starting to think the same way.
Hore will be 35 in September and was dropped to the reserves bench by coach Jamie Joseph for the Highlanders' 11th and latest defeat of the season - a particularly galling one against the Force in Perth in which they were leading with two minutes to play.
A key reason for Williams' departure would have been the young talent in his position. He has clearly been overtaken by Sam Whitelock, Luke Romano and Brodie Retallick, with 22-year-old Dominic Bird, set for a role against France next month due to Whitelock's finger injury, also probably ranked higher than Williams.
The All Blacks don't have that same depth at hooker. Hansen has only another veteran in Keven Mealamu (a 34-year-old for whom the clock is also ticking) and newcomer Dane Coles as his options. Beyond Coles there is no one obvious coming through. Corey Flynn and Hika Elliot have been overlooked and the next tier of Rhys Marshall, Codie Taylor, Ben Funnell and Liam Coltman are still probably a year or so away.
If Highlanders coach Joseph keeps picking Coltman ahead of his captain, though - and his team selection for Friday's match against the Blues in Dunedin will be interesting - it will be another reminder to Hore that he is past his best. If nothing else, Hore could call it quits after the France series to focus on the Highlanders next year, just as Williams intends to do at the Blues.
Tony Woodcock is in a similar position at the Highlanders. The All Blacks prop has had a wretched season since moving south from the Blues in a bid to rejuvenate his career. Instead it could have hastened its end.
The loosehead has been in and out of Joseph's team due to injury but even when playing he has been underwhelming. His experience against France could be considered valuable, and, at 32 he is still relatively young for a prop, but he must only be an outside chance to make the All Blacks' end of year tour tour. Ben Franks and Wyatt Crockett are playing far better, though of course Super Rugby form isn't necessarily the most important factor for Hansen.
Hore and Woodcock, two good mates nearing the end of their careers. Will they leave on their own terms or will they wait for the dreaded tap on the shoulder?
- Patrick McKendry of APNZ