Note to Googlers.
If there's one thing I learned from working in Yahoo during its crazy rise in the early 2000's, it's that you should sell when your founders / CEO sell!
Our stocks were almost doubling every 6 months, we thought we were invincible! Many of my colleagues joined when Yahoo stocks were at its highest, so they were holding off for more gain. I was lucky enough to have joined when it was close to its lowest at $9 a share, so I happily sold some. Boy am I glad I did.