SAN FRANCISCO -- Twitter Chief Executive Dick Costolo said this week that he's not worried about Facebook's launch of video on Instagram, which competes directly with his company's product Vine.
"Other people can replicate that or take pieces of it if that's what they want to do," Costolo said.
But one week into the battle for video between the two powerful social networks and Instagram appears to have -- at least temporarily -- dampened enthusiasm for Vine.
The sharing of Vine videos plunged on June 20, the day Instagram unveiled video for the first time, says Matt McGee, editor-in-chief of SearchEngineLand.com.
According to Topsy, there were almost 2.5 million Vine links shared on June 19. The next day only about 1.5 million were shared.