LinkedIn has been heavily broadcasting its mobile traffic numbers this week, but the company is also growing in other ways: since the start of the year the company has grown by 33 million users – from 277 million members at the start of the year to 300 million registered users today. That comes out to a staggering 6.6 million new members per month over the past 15 months. According to LinkedIn’s metrics, LinkedIn and Slideshare (which was bought by LinkedIn in 2012) combined for an average of 187 unique monthly users in Q4. LinkedIn only expects these numbers to grow as its mobile app for Slideshare will launch in the Android store soon. With an active and growing user base, LinkedIn is sure to start cashing in – it’s really just a matter of when.