Seagate (STX) was down over 9% today. As Fool senior technology analyst Eric Bleeker describes in this video, it committed an act ruled unforgivable in today's earnings environment. That is, it guided weakly. Previously, we've seen Apple sell off on its own weak guidance and VMware see its own 20% plunge today based on guidance that was in line with what Seagate provided.

The problem, Eric thinks, is that all of these companies are seen as an inflection point in their growth story. With Seagate, investors are now nervous about whether the company can continue pushing back against pricing wars and weakening PC demand in a hard disk drive space that's been the subject of fierce battles in recent years.