The system, at transcribe.naa.gov.au, basically allowed the public to register for an account, pick from hundreds of digitally scanned public records and correct any errors in the automatic text recognition (of which there's lots!)
For each record corrected, a user earns points, which accumulate on a leaderboard so they can compare themselves to others in a competitive way (I'm currently 40th).
This approach by itself is innovative and has only been previously used in Australia by the National Library, which has operated its newspaper archives in the same crowdsourcing way for around six years.
However the National Archives have taken an additional exciting step. Users can now use the points they gain from correcting archival transcripts to earn copies of Archives' publications, posters and files.
Essentially, rather than spending money on publications from the NAA, the public can 'earn' those publications by improving Australia's historic record.
Now that's a fantastic example of how to both involve the public and to reward them for participation in a meaningful way.
There might still be some further need required to tweak the system so that people feel the level of work they do is appropriate to the rewards - currently the cheapest reward, the Collections booklet requires 50,000 points - which only the top eight leaderboard members have reached. However this is the first time a government agency has taken this type of step, so some refinement is to be expected.
That said, I'm motivated to get back to work improving Australia's historic record and earning myself a material reward in thanks for doing so.