It's quite staggering to see the breadth of Zynga's social gaming empire, which raised over $40 million in its first round of venture capital funding.

Although no new investors have been mentioned (suggesting there aren't any - it's the same capitalists ploughing more money into the online gaming phenomenon), a second round of funding has added another $15.18 million to Zynga's enterprises, according to a regulatory filing.

The social gaming company currently enjoys the largest online game in terms of sheer number of players, Facebook app FarmVille, which currently has a staggering 65 million active players.

Zynga has stated that its sights are set on cracking the smartphone market, which could be the venture this $15 million is earmarked for.

To date, iPhone success has been limited, but the burgeoning trend for in-app purchases and micro-transactions on Apple's handheld are where Zynga's strengths are found, and could prove to be its key for unlocking the portable gaming market.

VentureBeat