We saw today how Google uses its own tools to run its business.

The Google toolbox keeps expanding as well. The latest two are advertising related and come as Google's acquisition of ad giant DoubleClick is finally approved.

Up this week:

Ad Manager

The new Ad Manager -- still in beta -- is targeted at small businesses that want help booking and running online ads. Sites would use the tool to serve up ads they book themselves, for no charge.

Google will make a buck by serving up ad slots that a site can't sell itself on a revenue share basis. The Ad Manager service will handle formats including graphical display, video and text ads.

Google said free Ad Manager would be used mainly by smaller businesses while similar ad serving solutions from DoubleClick would work better for larger publishers, for a fee.

Walk through the Ad Manager features here.

Performics SEO

It's strange to think about Google owning a search engine optimization (SEO) firm -- but it's true. SEO firm is part of the DoubleClick acquisition.

It's not clear what -- if anything -- Google will do with Performics. Clearly the DoubleClick deal was all about advertising.

But at least one search expert, Danny Sullivan, has called for Google to divest itself of Performics ASAP.

Worth watching...