Technology and web-search giants Google is without a doubt one of the most recognisable brand names on the planet today, with the company making an impact in everything from mobile operating systems to online searching.

Now though its market dominance may be set to backfire, as federal regulators in the US are set to hit Google with subpoenas, and launching formal investigations on whether the company has abused its online monopoly.

According to the Wall Street Journal, which cites “people familiar with the matter”, the civil probe is set to be the most serious in Google's history, although it won't necessarily lead to federal allegations or convictions.

The new inquiry is set to examine Google's core search-advertising business, which is also the company's most profitable sector. While having a monopoly isn't illegal under US law, it is illegal to abuse or acquire one unlawfully.

The federal probe is set to investigate whether Google search results unfairly steer users towards Google-owned or operated sites at the expense of competing services, something which many companies have accused the search giants of doing.

Fairsearch.org, a group representing several Google critics said that, “Google engages in anticompetitive behaviour that harms consumers by restricting the ability of other companies to compete to put the best products and services in front of Internet users, who should be allowed to pick winners and losers online, not Google.”

Several prominent websites, including Expedia, TripAdvisor and WebMD have accused Google of favouring its own services above theirs when displaying search results, depriving their sites of potential traffic.

Google has been rapidly expanding its plethora of online services in recent years, either creating new sites of its own or buying out the competition. What started as a simple web search model has now been expanded to include email (Gmail), online video (YouTube), local business listings (Google Places) and social networking (Google Buzz), to name but a few.