Google just suffered three new attacks against its already troubled core business

Google has a staggering number of projects going on right now.

The company is simultaneously weaving self-driving cars along San Francisco's roads and sending internet balloons floating all around the globe.

But for all that diversity, Google is still a search and ads company - that's where it makes about 90% of its revenue.

And that core business is under attack from a million directions at once.

Look at the last two days:

• On Monday, Microsoft announced that Bing would be taking over search and advertising for AOL, ousting Google for at least the next ten years.
• Today, Facebook introduced an attractive new ad buying option for marketers that makes its video ads more competitive with YouTube's.
• Pinterest also started rolling out its first buyable pins, a big step forward in its goal of becoming the visual search and discovery engine where users start looking when they have a glimmer of an idea of what they want to buy.

None of these things are immediately catastrophic for Google.

Losing the AOL deal is only "tens of millions" of dollars that Google won't make every few months - a drop in the bucket compared to the $17.26 billion in revenue it reeled in last quarter. And even though Facebook is becoming a bigger magnet for video ad dollars, YouTube is still enormous and much more established with advertisers. Pinterest's ad products are still relatively new, and Google is on the cusp of launching its own "Buy" button, too.

But the little cuts are adding up.

While Pinterest might just be beginning to capture visual search and subsequently up its ad offerings, Amazon's been yanking product searches away from Google for years. Desktop product search queries on Amazon increased 47% between September 2013 and September 2014, according to ComScore, threatening Google's especially lucrative kind of search advertising.

Losing the AOL deal comes less than a year after Mozilla replaced Google search with Yahoo, causing the former's largest drop in search marketshare since 2009.

Right now Google is the default search for Apple's Safari browser, but there's been talk that Apple could ditch it for Bing or Yahoo too. Regardless of whether that happens, Apple does plan to block ads in Safari on mobile with its next iOS update, at a time when Google is already losing 10% of its annual revenue to adblockers, according to PageFair, a company that monitors online ads.

Meanwhile, the amount Google can charge every time people click on its ads continues to decline, and overall growth was slower than expected last quarter, which has become a recurring theme for Google the past year.

Instead of seeing robust growth, Google's core business is going flat, right when competitors are chipping away at it.

As one former Google employee recently put it in a conversation about Google's future:

"Their core growth just is not obvious anymore."