Zynga, the owners of FarmVille, have put rumours to rest that the game was leaving Facebook by signing up to a five year strategic partnership with the social-networking site.

The agreement shows that Facebook means business when it comes to social gaming and to strengthen its games arm further, the social networker will be expanding the use of the site's digital money, Facebook Credits.

Although it's not been established who gets what money in the Facebook Credits system, more Zynga games will be using credits in the following months.

There was a rumour that Zynga was looking to pull out completely of Facebook and it seemed that Facebook Credits was the sticking point, so it's no wonder this is a big part of the announcement.

Games pioneer

Speaking about the link-up, Mark Pincus, founder and chief executive officer at Zynga, said: "Facebook was a pioneer in opening their platform in 2007 and in just three years tens of millions of Facebook users play our games everyday, from FarmVille and Cafe World to Treasure Isle and Mafia Wars,"

"We are excited about Facebook's long-term commitment to social gaming and Zynga, and look forward to working with them and other platform providers to bring the best social gaming experience to users worldwide."

Last year, Facebook exclusively told TechRadar that FarmVille had more members than micro-blogging site Twitter.