Steve Ballmer and Microsoft have shut down the Kin social phone project, due to weak sales. An understandable decision; we estimate the Kin captured less than 0.1% of the US handset market in Q2 2010. At least 8 major reasons caused its downfall:

1. Clumsy sub-branding with "Kin";
2. An unattractive handset formfactor that did not wow young users;
3. An unexciting set of features and consumer media;
4. Suboptimal finger-based touchscreen user-experience;
5. Poor marketing of its automated cloud-storage backup service;
6. Mixed integration of the UNIX-Java Danger acquisition;
7. Weak reception from US developers, who couldn’t run downloadable apps or use Flash;
8. High handset and data-plan costs at Verizon Wireless.

This is a long list of failure points. The Kin joins several mobile and portable product flops from Microsoft, such as Courier, Zune and Pocket PC. Will Microsoft and its handset partners learn the lessons of the Kin for Windows Phone 7 in 2011? They will need to, as Microsoft's global smartphone OS marketshare is near a record low.

Reasons 2, 3 and 4 should be Microsoft's and its device partners' priorities. Good-looking touch-smartphones with fun consumer media services and a slick UX will attract developers and persuade tier-1 US carriers to throw subsidies in their direction. Add in Reason 5, the automated cloud backup for data, which was one of the Kin's few differentiators, and Microsoft's prospects will look brighter. And if they could bring the popular Xbox sub-brand and services to the table, then Microsoft's prospects may look even brighter still.

But Microsoft will have to move with urgency, because rivals like Apple, Android and MeeGo are not standing still. If Microsoft struggles to deliver in any way on WP7 in 2011, then I believe it will eventually have to buy its way into the mobile market. Smartphones will soon outsell PCs and mobile is too big a market for Microsoft to ignore. Who do you think Microsoft should buy in software or hardware? And why? Leave your suggestions in our Comments box.