In a Friday blog post, Tech-Thoughts' analyst Sameer Singh said that the Windows 8 app-for-cash promotion - dubbed `Keep the Cash' - has been launched by Microsoft this week because the ongoing quarter has witnessed a slow growth of the company's app store, the Windows Store.

Pointing out that the month-on-month growth of the Windows Store has slowed to "just 10-15%," Singh said in the blog post that Microsoft has responded to the slowed growth with the Tuesday launch of `Keep the Cash' promotion, under which the company is "offering developers $100 to publish an app on the Windows Store."

According to Singh, the rules of Microsoft's `Keep the Cash' promotion - which ends June 30 - are that developers are being given $100 for every new app that they publish to the Windows Store. The maximum number of apps, for which developers will get $100 per app, is 10.

Singh's observation that the Windows Store growth has slowed this quarter is based on the use of MetroStore Scanner for ascertaining app growth. The MetroStore Scanner figures have revealed that, after a 52 percent increase in December 2012 over November, there was a dramatic slow down of Windows Store gains.

Going by the MetroStore Scanner statistics, the total in January was 10 percent more than the December figures; while February posted a 9 percent gain. In March so far, the Windows Store app count is 12 percent higher than the February count; with the store currently boasting around 50,000 apps.