Google is paying up to $75 million to buy Jambool, a San Francisco virtual currency startup founded by former Amazon.com employees Vikas Gupta and Reza Hussein, according to a report in TechCrunch. TechCrunch, citing unnamed sources, puts the price tag for Jambool at $55 million plus another $15 million to $20 million if certain milestones are met. Jambool describes its Social Gold virtual currency system as the "no-hassle, scalable way to build your virtual economy."

If the purchase price is accurate, it would be a significant win for Seattle's Madrona Venture Group which led Jambool's $5 million venture round last summer. It is unclear how much Madrona invested as part of that deal and the total equity ownership that it held in Jambool.

But it does appear to be a pretty solid return, marking the first payout this year for the Seattle venture capital firm. Madrona's last significant M&A deal occurred in 2008 when Microsoft purchased online travel site Farecast for $115 million. Madrona had invested $5.5 million in Farecast for a 23 percent stake, earning the venture firm about $26 million.

However, it took Farecast about five years to reach its exit. In the case of Jambool, it appears that the payout came almost exactly one year after the $5 million investment.

A representative for Madrona declined to comment on the TechCrunch report. (Madrona is represented on the Jambool board by Scott Jacobson).

We've also reached out to Jambool, and we'll update this post if we hear anything more.

Google has been on a bit of a buying spree this year, most recently acquiring the social media startup Slide for a reported price of $182 million. But that's not the only company that the search titan has gobbled up this year. According to this acquisition list, Google has made 18 acquisitions so far this year including the reported deal for Jambool