NEW YORK ( TheStreet) -- If there's a stark difference between companies that play in the mobile arena, it's that hardware pays, and advertising doesn't. At least not yet. Even though Google's ( GOOG) Thursday's earnings release snafu was caused by printer R.R. Donnelly ( RRD), Google has bigger fish to fry than that -- how to tackle the mobile game. Third quarter earnings from Google were worse than expected, as cost-per-click (CPC), a key metric for Google, fell sharply year over year and quarter over quarter, highlighting the fact mobile ads are still not as profitable as desktop ads. Wall Street analysts were expecting CPC to bottom out this quarter. That hasn't happened. Google said CPC fell 15% year over year, and 3% quarter over quarter. As a result, third-quarter earnings, excluding Motorola, came in at $9.03 a share on $11.33 billion in revenue. Analysts polled by Thomson Reuters were looking for Google to earn $10.65 a share on $11.862 billion in revenue for the third quarter. Google Earnings Leak: Blog Recap On the conference call Thursday, CEO Larry Page said mobile revenue had an annual run rate of $8 billion, including Google Play. "That's some business," Page said. Even though mobile revenue has ramped up from $2.5 billion to $8 billion on an annual basis, it's still not enough, as the world is going increasingly mobile. Bank of America Merrill Lynch analyst Justin Post downgraded Google to neutral with a $745 price target, not only on concerns over mobile monetization, but PC revenue deceleration as well. "We are moving to the cautious camp and downgrading Google to Neutral from Buy (we've been a Buy since 2006) as we think the mobile transition is accelerating, and more difficult quarters are likely in 2013," Post wrote in his note. Oppenheimer analyst Jason Helfstein also downgraded Google shares. He lowered his rating to perform with a $695 price target on concerns over Nexus advertising spending, and Motorola concerns.