Callpage - Turn website visitors into sales calls. Use CallPage and provide immediate free phone callback to your leads in 28 seconds.
CallTrackingMetrics - Know who is calling and how they found you. Maximize the return on your advertising.
Upcall - Upcall enables you to crowdsource your outbound calls. Collaborate with 1000+ on-demand callers worldwide for sales, marketing and customer support calls. Free trial.
DialogTech - DialogTech is an end-to-end call attribution and conversion platform.
HeyHi.sg - Video call with interactive whiteboard
Marchex - Marchex is a mobile advertising analytics company that connects online behavior to real-world, offline actions.