Google Voice - Google Voice gives you one number for all your phones, voicemail organized in an email format, free...

DialogTech - DialogTech is an end-to-end call attribution and conversion platform.

TextMe - TextMe is a free calls and messaging application at both local and international levels.

Invoca - Call tracking & analytics software

Talkatone - Android App on. Google Play. Stop paying for cell minutes, texts & landlines; Turn your iPad or iPod touch into a phone; Call/Text even in areas with bad cell coverage; Call/Text when travelling without paying for expensive international minutes.

CallTrackingMetrics - Know who is calling and how they found you. Maximize the return on your advertising.