It was 'Joe the Plumber' in the last US presidential elections, and the British Labour Party had 'Mondeo Man'. These are the personalised manifestations that political parties often attempt to imbue their political messages with.
New Zealand Labour has (so far): 'guy sitting at his kitchen table in West Auckland doing his GST return', 'Rangitikei truck driver', and now 'neighbour of sickness beneficiary painting his roof'. Apart from the obvious need to choose one and give him a more usable handle (Chris Trotter calls him 'Waitakere Man'), finding an acceptable characterisation of the all-important swinging voter is proving troublesome for Labour.
This mythical voter is usually male, middle aged, straight, has kids, is invariably of European descent, unlikely to be tertiary educated and either self employed or earn a modestly above-average pay packet. While this group has not lost as much economic ground as beneficiaries and the working poor over the last thirty years, their real incomes have still gone backwards or stagnated, and they have increasingly been shut out of many previously universal state benefits - having to fork out for their kids tertiary education for example.
But this group has also lost ground in other ways. Our society used to orbit around this demographic - both at home and in public. Social change over the last forty years has seen everyone else assert their rights and place in the sun: women, gays and Maori in particular. Amongst this group this has caused a level of resentment and anxiety that mainstream parties orientate towards because it is a powerful motivator, and this demographic not only vote, but change their votes from one election to the next. The trick for politicians is to make the right noises, indicating that they understand and share their concerns without actually stating it openly (thereby alienating a huge number of other voters). Hence the 'dog-whistle' tag - inaudible to some but the target audience knows exactly what they mean.
David Shearer's roof painting incarnation broke one of the basic rules of this (quite old and worn) political strategy. The negative attack on beneficiaries was actually audible to all - particularly Labour's activist base - and as a result it has backfired badly. The neighbour has been forgotten and the focus has gone onto the beneficiary. Scott Yorke has a well-written piece that exemplifies the reaction - see: I'm The Guy Painting His Roof.