Google (NASDAQ:GOOG) is an engineer’s paradise. Besides having access to millions of users and seemingly unlimited resources — with about $42 billion in cash — the company has a unique philosophy. That is, an engineer can spend 20% of his or her time on anything that’s interesting.

But the results can be — and have been — messy. Even though Google’s engineers are top-notch, they still come up with some big duds. But at least the company knows when to call it quits — last week, Google announced that it is dumping some of these failures.

One of the aforementioned duds is Jaiku. Haven’t heard of it? Well, you’re not alone. Other than having a tough name to remember, the social web app got little traction. Google Jaiku allowed users to send updates to friends in a microblogging format — think Twitter. Except it’s not Twitter. Not necessarily compelling when millions are using Twitter, as well as Facebook and even Google’s own G+ social networking service.

Google also is giving up on another earlier attempt at social networking, Buzz — a service that did not live up to its name. However, Buzz will not completely go away — instead, it will be folded into Google+, which has been growing like a weed (at last count, there were 40 million users).

The recent axing of the weak is just the latest example of Google’s shotgun strategy, in which the company produces several hits and several misses. Looking back at Google’s history, there’s been plenty more. Here are some of Google’s hits, misses and a couple projects whose final judgment still is in the air:

The Good

The 20%-time approach has not just been a fun thing for engineers. It actually has been the inspiration for a variety of game-changing services, including Gmail and Google News. Gmail is the No. 3 email provider with more than 190 users, and Google News gets about 7.9 million unique monthly visitors, according to Compete.com.

However, Google also realizes that it must go beyond its own walls to find innovation. Granted, this strategy is risky. Many other tech companies — like Hewlett-Packard (NYSE:HPQ) and AOL (NYSE:AOL) — have had disastrous results with acquisitions. But for the most part, Google has been successful. The company knows how to integrate engineering teams and get them acclimated to the overall culture.

Often, Google will focus on smaller companies that have compelling technologies. This was the case with its acquisition of Android back in 2005. The company’s code became the basis of a fast-growing mobile operating system. At last count, Android activated 190 million devices across the world, with revenues reaching $2.5 billion for 2011.

The Bad

Jaiku and Buzz are far from Google’s only failures — Google has made lots of bad products — or at least those that attracted few users.

One is Google Health, which was pretty sickly. While the medical records market is a huge opportunity, the competition is fierce, including names like Microsoft (NASDAQ:MSFT), Allscripts Healthcare Solutions (NASDAQ:MDRX) and Practice Fusion. The company announced Google Health’s demise this year.

Then there was the laughable Google Wave. It was launched in the summer of 2009 to much fanfare, but Wave puddled out. The technology was meant to merge classic email with real-time communications, but users had a hard time figuring out the complex system, and it dried up in 2010.

Then there was Google Video Player. The timing was right — the service came online in 2005 — but it never caught on, with users instead sticking to a number of video streaming services already available. Still, Google realized that video was highly strategic and shelled out $1.65 billion for YouTube in 2006. Video Player was pronounced dead in 2007.

The Middling

Some of Google’s projects are too young to make a call on. And Google Flights certainly fits in this category.

Google leveraged its $700 million acquisition of ITA Software to create the travel site this year. Google Flights is incredibly fast and has some cool mapping features. But the flight information is not robust, at least compared to rivals like Kayak. Not to mention, Google Flights has to try to gain ground against entrenched competitors Priceline (NASDAQ:PCLN) and Expedia (NASDAQ:EXPE), which have strong brands as well as thriving global businesses.

Another Google service that the jury still is out on is Google+. Even though it is getting lots of traction — remember, 40 million users — the social network still has some nagging concerns.

For one, there might be a lack of user engagement. After all, what do you do when you get to G+? While it’s like Facebook in function, and it has a few nifty tools, it still doesn’t have the game and app power of Facebook — and many users are finding that it doesn’t have as many of their friends, either.

Even Google’s own workers aren’t sold on Google. Last week, one of the company’s engineers, Steve Yegge, accidentally posted to the public his complaints about the service. At the core, he thinks Google is too product-driven, which means things often are loosely connected. Instead, Yegge thinks a better approach is to make G+ into a platform, which would allow for easier third-party app development.

Tom Taulli runs the InvestorPlace blog “IPO Playbook,” a site dedicated to the hottest news and rumors about initial public offerings. He is also the author of “All About Short Selling” and “All About Commodities.” Follow him on Twitter @ttaulli. As of this writing, he did not own a positioning any of the stocks named here.