Buy a hamburger and get rewarded with Facebook Credits to spend on a virtual cow. That's the mouth-watering promise of startup <a href="https://www.plink.com/">Plink</a>, which is launching a virtual
<img class="shot2" src="http://tctechcrunch.files.wordpress.com/2010/04/plink.jpg" alt="" /><a href="http://google.com">Google</a> has purchased mobile visual search startup <a href="http://www.plinka