Which One is Better?
Both social network sites are of course different, but you might be surprised to find out which one can bring about the most for your money. Both offer the opportunity for your company's ad to be shown on the various pages that people will frequent, such as their personal homepage, usually the profile page.
Both offer the ability for businesses to customize which groups of people can see their ads, based on location, gender, interests, age, etc.
The two main differences however are that of the price that a company pays and the exposure. Facebook is superior in this category, as the price that a company pays when someone clicks on their ad is much less than what you would pay using LinkedIn.
In LinkedIn's favor, however, the 24 hour approval period can ensure that only those serious ads are displayed on the website and thus, on a member's profile page. Facebook may have a screen that ensures that ads aren't too explicit, but there is no 24 hour approval period.
Then there is a matter of exposure - Facebook does have a better exposure for ads than that of LinkedIn, though for some users of the former social site, it is as issue of over exposure. In this case, a user may not see the ad or be using a means in which to block ads from showing.
In terms of the differences between CPC and CPM, it may do a business better in the long run by using Facebook, especially if offering different sales or that of a special event. The click per person option allows not only for fans of a business on Facebook to click on the ad or event, but to even RSVP to the event.
With the clicks per impression (usually a thousand), a business may want to go with LinkedIn, if just to be seen by other businesses and professionals. Because of the very purpose of LinkedIn, businesses may find that for exposure, even if on the pricey side, LinkedIn is the way to go.