Google updates hit webmasters hard (see all of Google’s updates and algorithm changes), and sometimes causes drastic decline in traffic that’s seriously difficult to recover from. Organic traffic is what drives websites, and generates revenue. A drop in traffic means severe reductions in advertising revenue and can cause some websites to go broke.
If your website has been slapped with a Google penalty, this handy infographic by Promodo might help you get back on your feet.
Click to enlarge.