The company said that of those 100 million people, 80% are accessing the platform via mobiles on a continent with very low Internet penetration and smartphone ownership.
Facebook's global mobile ad revenue jumped more than 150% in the second quarter, accounting for about 62% of overall ad revenue, Reuters noted.
Seven in 10 African consumers access the Internet through their mobile phones, compared with 6% who use desktop computers, according to an Ericsson study earlier this year.
Facebook would be pouring more resources into Africa to understand how consumers use its product and was considering opening an office on the continent in 2015, said Nicola Mendelsohn, Facebook's VP for Europe, Middle East and Africa.
Shares of Facebook are slightly higher at $77.37
TheStreet Ratings team rates FACEBOOK INC as a Hold with a ratings score of C+. TheStreet Ratings Team has this to say about their recommendation:
"We rate FACEBOOK INC (FB) a HOLD. The primary factors that have impacted our rating are mixed some indicating strength, some showing weaknesses, with little evidence to justify the expectation of either a positive or negative performance for this stock relative to most other stocks. The company's strengths can be seen in multiple areas, such as its robust revenue growth, largely solid financial position with reasonable debt levels by most measures and impressive record of earnings per share growth. However, as a counter to these strengths, we find that the stock itself is trading at a premium valuation."