They kept both the title and cast secret until shortly before the première; instead dropping cryptic teasers to create a viral effect.

This can drive new customer acquisition and can have viral effects.

I wonder whether the constant talking-up of the opposition's chances have a viral effect on Irish confidence or is it necessary, to drive for further glory?

Crowdcasting competitions have a viral effect, as interested participants refer others to the event.

As well as the usual viral effects, Freshers' Flu can also have some psychological effects.

Mr. Crichton said that he, too, had long hungered for a forum like IQ2 U.S., "and I hope it has some sort of viral effect."

With one click, they find themselves invited to join Formspring and to send invitations to their Facebook friends, creating a "viral" effect.

"A viral effect?"

The viral effect of Twitter has been remarkable.

It has a viral effect.