By now everyone should have realised that daily free promotional sites such as FreeAppADay and Free Game of the Day work - at least in terms of driving games up the free charts.

Indeed, despite only launching last week it seems that indie-focused outfit FreeAppCalender is also turning the wheels of promotion.

Filipino developer Kuyi Mobile has just written up a great post about its experience taking its Card Drop game free.

"Card Drop became the site's flagship game and was made free on March 14, 2010," it explains.

"We've extended the free promo for 24 more hours (because the first 24 hour response was huge!) and we got as high as #4 on the top free card games in the US and received over 15,000 downloads in 48 hours."

In terms of actually making money out of the exercise, Kuyi Mobile cross-promoted its free SOW game, selling 40 percent more in-app purchase packs in the process.

[source: Digital Sinigang]