Google has been doing a lot to make search more social, but the search giant continues to leave out your friends’ Facebook content from its results. Sure, you may find people from your social circle (as defined by Google) in the mix, but hundreds of millions of people use Facebook, and many of them use it as their primary social network – the one where they communicate the most with their closest friends and family.

Do you think Facebook integration would improve the Google experience? Tell us what you think.

Facebook data can improve search for a variety of reasons tied to that point. One reason is that of recommendations, even if they’re inadvertent. People say positive and negative things about experiences they have with brands, places, movies, music, food, etc. This occurs naturally all the time. This information – based on people you know (and know whether or not you trust or care about their opinion) can provide a great deal of relevance to a query.

Another reason is photos. Imagine how nice it would be to see photos from your friends turn up for relevant queries. Let’s say you want to take a vacation in Maui. You could search for pictures of Maui on Google and find some beautiful shots no doubt. How nice would it be to see your friends’ honeymoon pictures in the mix? See the fun things they did while they were there. You may not have even known they went there, but if their photos surfaced in your Google search, you would know, and possibly be led to discuss their experience with them.

Videos are another reason. People are posting more and more videos on Facebook – both original and links to interesting or entertaining things they’ve found on the web. In relevant cases, wouldn’t it be nice to see videos from your friends when they make sense. You can apply the Maui example here as well. Or let’s say you’re searching for “TV on the Radio” videos, but not one specifically. Maybe you could see some specific ones that your friends thought were particularly cool.

But Google does not include this kind of personalized Facebook data in its search results, and there is nothing indicating that this is on the way either. Bing uses more personalized Facebook data, but not in this rich of an experience.

Meanwhile, third-parties are busy finding solutions to problems like this. Greplin and Wajam are two examples. Granted, neither of these services offer the perfect solution to create the kind of rich search experience I’m describing, but they’re making strides where the big search engines are slow to adapt to user needs.

For example, Wajam launched a new feature for its browser plugins, which allow you to control which Twitter and Facebook friends you want to be included in your search results.

There’s a good chance you don’t in fact care about the opinion of everybody you’re friends with on Facebook. Just because you knew somebody in High School doesn’t mean you care about their opinions on Mexican food. However, your friend that provides an awesome cuisine every time you go to their house for a dinner party might carry more weight.

On the other hand, you never know what you’re going to be searching for down the road, and whose words may have some hidden and unexpected relevance. Maybe you are friends with someone who has the complete opposite taste in movies as you. If they say a movie sucks, maybe you’ll be more inclined to watch it.

That’s beside the point.

The point is that Facebook content has the potential to make search better when integrated in interesting and relevant ways. This is one reason why Facebook itself could be a dangerous match for Google, if it ever decided to start taking search more seriously.

To some, the notion may seem odd, but it didn’t take long for a new-ish search engine called Bing to gain significant ground in the search market. And Facebook’s user-base is enormous. A solid marketing budget can go a long way, as Microsoft proved with Bing. Then of course there’s that whole Bing-Facebook partnership thing. Bing powers Facebook’s web results and Bing will no doubt find new ways to integrate Facebook into its own experience.

Earlier this week, Experian Hitwise research came out, finding that Google has lost ground to the Bing-Yahoo alliance six months in a row in the U.S.

Does Google need to give users personalized Facebook results? Share your thoughts.