Spoofed websites for popular social apps have been observed for some time now - recent reports from Malwarebytes show that one of the most popular mobile app - WhatsApp has been targetted recently as well.
The particular site at question aimed at Russian speakers and offered app download for broad scope of mobile devices - IOS, Android, Windows Phone and Blackberry. The site was resambling the legitimate website quite a bit with lot of code scrambled from the oficial website. The unsuspecting users downloading the application would get infected by variant of Android SMS Trojan that once installed would start sending text messages to premium rate numbers.
Reference:
Spoofed Whatsapp site delivers polymorphic SMS Trojan
http://www.net-security.org/malware_news.php?id=2687WhatsApp gets Rogue Download Page
http://blog.malwarebytes.org/mobile-2/2014/01/whatsapp-gets-rogue-download-page