The world's most popular smartphone operating system, Google Inc.'s (GOOG) Android OS, can't seem to catch a break these days.  If its not being attacked in court [1][2][3][4][5] by rival smartphone maker Apple, Inc. (AAPL) whose looking to forcibly remove its products from market [1][2] with lawsuits, it's being probed by antitrust investigators.

The U.S. Federal Trade Commission on Wednesday issued long awaited subpoenas.  For those of you who aren't lawyers and haven't been dragged through a major court case, a "subpoena" is a government demand for testimony or evidence.  Failure to give the requested information can result in criminal and/or civil penalties.

The fact that the U.S. government has issued subpoenas shows that it's getting serious about its investigation of Google.  A Google spokeswoman seemed nonchalant, commenting, "We understand that with success comes scrutiny. We're happy to answer any questions they have about our business."

But for all the cheer, the move is a major concern for Google.

Several small smartphone service providers have claimed that Google applied pressure to its hardware partners to boot their products off their smartphones, in favor of Google's rival services.  In and of itself, that might not be illegal were, Google not by far the industry's most dominant player in sales.  Android is reportedly outselling the next closest company, Apple, 5-to-2 in recent figures.  Thus if Google is found guilty of the allegations, it could face stiff penalties for violating antitrust laws.

Other allegations against Google include reports that it stole data from other services, such as reviews site Yelp and used it to bolster its own offerings.  And Google also stands of artificially boosting its services above competitors' in the results from its search engine -- the most used search engine on the planet.

The issue of the subpoenas was first reported by The Wall Street Journal.  Even if Google can beat the antitrust rap in the U.S. it faces similar accusations in Europe, a place known for its strict antitrust laws [1][2].  

Google has set aside $500M USD in cash to cover possible antitrust penalties.  The question is whether that will be close to enough.