I have several sites that have ranked well for a long time. In March I started doing some link building using Fiverr. Normally I don't use the gmail account that was setup when I opened my Google account, but I was having trouble opening a Fiverr account with my regular email, so I used the gmail account to get access. What I did not realize is all of the emails from Fiverr were going to my gmail account. Including the ones with all of the link building details.
In April, after these links were built, I suffered a two-thirds loss in traffic only on the sites that I built links to that were included in the Gmail emails.
Is it possible that Google used the information in the Gmail emails to penalize my sites?