This has ramifications for how you use it, particularly if you are promoting products and services. If this is your aim, you should hold back on the overt promotion. After all, in both online and offline situations people don't like hard selling -- particularly if it occurs in a primarily social setting.
It helps to imagine going to some real-life offline social event. If you did that, you'd want to make a good impression by being an interesting and polite conversationalist. You would always reply to questions asked of you. You would be helpful. You would mingle. And you would only start to endorse things if they were in the context of the conversations you were having.
A recent personal example comes to mind: While at a Christmas party I got chatting to a relative about health. Turned out we had similar issues. After a few minutes conversation I recommended a naturopath I'd been seeing and she wrote down the name of a particular herbal product that worked for her.
I think promoting on Facebook works best if it's carried out in a similar manner. You've got to socialize with people first, get to know them a little. Develop some rapport so that they like you (and vice versa). Then let the promotion and selling develop organically and in context.