The proliferation of online data sourced from either unknown populations or non-probability-based sampling frames provides both opportunities and pitfalls for political behaviour researchers. Recent studies have tentatively endorsed the capacity of one such source – Google Trends data – to measure issue salience in the United Kingdom, Spain and the United States. Google Trends data report the prevalence of search terms entered to Google on a weekly basis, and are freely available via Google. Using data from a time series of Australian opinion surveys – the ANUpoll series of public opinion – this paper has two aims: first, to reproduce analyses from these recent studies to examine the content validity of Google Trends data in the Australian case against probability-based survey data; and second, to use both probability-based survey data and the Google Trends data to predict temporal variation in Australians’ satisfaction with the direction of their country. The findings have positive implications for the external validation of attitudinal survey research, particularly in the face of declining response rates for traditional survey modes and adoption of accessible, non-probabilistic sampling frames.