The corporate venturing unit, which was set up in March, had done one deal before its parent was bought by WPP.

Google Ventures is hoovering up early stage deals in a fairly unusual move for the venture unit of a large corporate.

The US-based search engine backs the seed round of mobile and social application developer Nettle, which has been running for less than a year.

The social gaming start-up becomes the latest online company to get funding from Google.

US-based file sharing company Minus has raised the funds less than a year after it was founded.

Google's corporate venturing unit is reportedly among the backers of TechCrunch founder Keith Teare's latest venture.

Google and Qualcomm were joined by venture firms including IA Ventures and Metamorphic Ventures in the seed financing.

Earlier in the year, Stanford university graduates Tim Su, Astrid's co-founder and chief technology officer, and Jon Paris, Astrid co-founder and chief executive, joined the start-up accelerator AngelPad, which was set up by a group of ex-Google executives and has previously seen incubees Crittercism and Shopobot receive Google Ventures backing.

The US internet services firms have paired for at least a second time to back a graduate of the AngelPad accelerator programme along with Kleiner Perkins Caufield & Byers and others.

Alongside AOL Ventures in the Impermium round were venture capital firms Accel Partners, Charles River Ventures, Freestyle Capital, Greylock Discovery Fund and Morado Ventures, and angel investors Archimedes Capital and Embarcadero Ventures.