WPP, which includes PR firms Burson-Marsteller, Hill & Knowlton, and Ogilvy, among others, said in a statement that the growth in PR reflects "the positive impact of the sector's growth of fact-based polling techniques and social networking on the web."
Overall, WPP reported company revenue was about $6.2 billion (£3.339 billion), a 14.3% increase from the same period last year.
With an estimated net new business billings of $2.52 billion (£1.29 billion), WPP also reported net income of about $557.5 million (£299.9 million) for the first half of 2008.
Advertising and media investment management saw a 4.3% increase in revenue, while branding and identity, and healthcare and specialist communications saw the largest constant currency revenue increase: 14.7%.
In looking at revenue by region, Asia Pacific, Latin America, Africa, and the Middle East reported 26.7% revenue growth, with Europe reporting 20.5%, North America 7.0%, and the UK 4.6%.