Online advertising revenues continue to climb upwards, according to June 2012 figures from the IAB and PricewaterhouseCoopers (PwC). Revenues in Q1 set a new peak of $8.4 billion, representing a 15% increase from Q1 2011’s $7.3 billion. Despite this solid growth rate, it actually represents a slowdown from Q4, which grew at a more rapid 20.4% year-over-year, to $8.94 billion. The Q1 growth rate of 15% compares with 17.47% projected growth this year in US wired and mobile internet advertising spending, per a separate report released in June by PwC. Read the rest at MarketingCharts.