By the way, the "Sent from Tapatalk" signature is an option inside of Tapatalk. Most people probably don't know that it's there or don't care enough to disable it, just like the "Sent from my mobile device" in most email clients.
It's always important to reach customers where they are. Getting back into Tapatalk would accomplish this.
Tapatalk (paid version) was also a free app from either GetJar or Amazon Appstore. So that probably greatly increased its users.