ShareThis, the Palo Alto-based makers of the ubiquitous "social sharing" buttons on the web, today announced that it secured $23 million in Series C funding and acquired Socialize, which helps to make mobile apps social.

The acquisition will help publishers understand how content is performing socially across both desktop and mobile devices, by integrating the two companies' dashboards together.

"We've seen mobile sharing traffic double over the past year so there's a massive opportunity to combine our deep knowledge of social audiences and the most engaging content to create truly compelling mobile ad executions," said Kurt Abrahamson, CEO of ShareThis.

Socialize CEO Daniel Odio said his company allows users of the same app to communicate with each other inside and outside of social media sites.

"Mobile app users typically have no idea who the other users of the same app are. It's like everyone's in the same room... with the lights off," he said.

The new round of Series C funding, which puts the ShareThis' total funding at $54 million, was led by T-Venture, the venture capital company of Deutsche Telekom. The company said it plans to use the new money for product development and market expansion.

Bernhard Gold of T-Venture will join the company's board of directors.

Other investors in funding round include Blue Chip Venture Company, DFJ, Illinois Ventures, Matthew Pritzker Company, Mercury Fund and RPM Ventures.

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