Let’s be honest, it can be a lot of fun when rivals try to mess with each other’s big launch events. Thus, Twitter just put up a vague blog post that promises more features to come for its popular Vine video app. And as AllThingsD just reported, a new video offering from its Instagram photo-sharing unit will be the sole product launch at a Facebook event this Thursday. Which means, it was time for Twitter, which has the most popular such product in the space, to crow. “Over the next few weeks, we’ll be introducing some exciting new parts of Vine,” said its blog post today. “As always, we’ll share details on updates as we release them.” Instagram plans to release its video product at a press event at the social networking giant’s headquarters, according to sources, marking the first time the robust, 100-million user photo-sharing network will offer more than static images.