In social media, as in real life, it's prudent to be selective in one's relationships. As much as it's desirable to establish a great number of connections and relationships for your business, have a care about indiscriminate fan relationships. The closer the alignment your business has with your personal passions, strengths, interests and beliefs the easier it should be to select individuals, groups, other businesses and causes to be fans of.
There are two primary purposes to be a fan of relatively narrow list:
1. Your market niche and specific target -- If you start with the assumption, which I taken as a given truth, that the path to business success and prosperity lies in defining a specific target market, with a narrow, definable and easily conveyed appeal, then you want to attend to your alliances, whether they are real or just perceived. For example, if your target market is New York Yankees baseball fans, it probably wouldn't be a good idea to publicly become a fan of the Boston Red Sox. You could logically be a fan of overall Major League baseball sites, or the Baseball Hall of Fame, but to give the impression of allegiance to a competitive team confuses the issue and die-hard Yankees fans be less likely to have great loyalty to your business presence. You'll also want to avoid having too many alliances - that, too weakens your core message. The more you dilute your business's social message presence with contradictory alliances or large numbers of unrelated alliances, the less effective it will be.
2. The Piling On Effect - Another reason to be a selective fan is the very real chance that if you happen to become a fan of an entity that has a strong stance on one side of a controversial issue (whether or not you're aware of that stance) is that people who hold the other side will ignore you or and have negative thoughts about your business. You also may find yourself flooded with fan requests from groups aligned with the side of the original entity. The point here is you can find yourself on a side of an issue whether you wish to or not, and your primary business message and presence can be lost or even hurt.
The more clarity you have about your business social media presence purpose and goals, the easier it is to choose alliances. Just because someone asks or suggests that you become a fan, a friend or a follower doesn't mean that you have to agree.