Google is being sued by companies which claim that the search engine has been charging more money than it should have for the search based ads.

Google, whose income is generated mostly from online ads, allows its clients to specify a daily budget they would be willing to pay. When that budget is reached, the company's ads are no longer displayed that day.

In the complaint filed at the Santa Clara State Superior Court, CLRB Hanson Industries LLC and another company are accusing the search engine that it has exceeded those daily budgets.

It's not clear yet what are the financial claims of the two companies, because the damages cannot be appraised yet and it hasn't been actually proven if the rules that govern Google's advertising system have been broken. The lawyers of the two companies haven't made any comments, and the Google's spokesperson stressed that the allegations are unfounded and that Google will defend itself against them.

At the end of June, another company, Click Defense, announced its intentions to sue Google for not protecting its clients from click frauds.

This type of frauds implies that companies are paying for an ad, without having a real benefit; this is due to programs that simulate clicking on the ads.