They still seem to have created a model that fit the outcomes. There's no cross-validation here (since there's only two data points).
The real question is whether they can take this fitted model and apply it to future movies.
The real question is whether they can take this fitted model and apply it to future movies.
If the prediction can be moved from one week out to a month or more out from the release of the film, there may be actual applications. For instance, helping theaters decide which movies to show and on how many screens, or how many weeks to run a movie for.
Even without practical information it is still a good demonstration of the type of information that can be extracted from twitter that would have been very hard previously online.