Facebook wants to help users find and "Like" other Pages. One way they do this is by offering relevant suggestions to other Pages when you "Like" a new Page. See below: You’ve likely seen this …when you “Like” a Page, you get a series of suggested Page recommendations with easy access to “Like.”
These recommendations are not paid ads. Facebook simply offers this and bases suggestions on location, category, and other pages “Liked” by fans of your page. Fans can hover over a suggested page’s thumbnail to “Like” it right away, or click on it to go check out the page. Or, they can click “See All” to be taken to the full “Like Your Favorite Pages” browser. It’s helpful that the suggested pages are supposed to be based on fans’ interests, but it can be a distraction from a new fan spending more time on your page, which they just “Liked.” Suggested pages are a quick temptation to leave and go on to a new Facebook page. At their worst, they can recommend competing fan pages to your new fans.
See this Sears example:
This shows Page suggestions of brands that compete with Sears.
As well, Facebook has added another dimension.... Now, suggestions are not only when you are on a new Page, but if you are on a specific post (as shown below), you may also get Facebook's "Suggestions" as you get ready to comment.
That's a key question.
If you turn off Page Suggestions, then visitors coming to your Page and "Liking" it will not get the suggestions of other similar pages to Like. This can be a good thing.
HOWEVER, the trade-off for turning this off is that your Page will never appear as a "suggestion" to a user on another Facebook Page.
So the choice is yours to make as to whether the value of being a suggestion outweighs the potential downside of having related competitors appear as a suggest as soon as someone "Likes" your page. That's a decision you'll have to make!
Let's get back to the details of controlling this feature...
Participation in Page Suggestions is voluntary. It can be turned off. As noted, be aware that if you opt out of having suggestions shown to your new fans, then your page won’t be suggested to new fans of other pages. It’s a trade-off you need to evaluate.
So there you have it! The choice is yours.
Facebook continues to evolve and offer new tools and new features on existing tools (such as "Like" suggestions on posts). Hopefully this helps you understand the features and the decisions, along with implications, you get to make!