I used to claim to think that social interaction by email is not significantly different qua social interaction from face-to-face interaction. But the fact that I typically strongly preferred email interaction to face-to-face interactions is evidence that it's significantly different, and given my introvertive tendencies, it is evidence that it is less social. People like I need significant time "without social interaction" to avoid exhaustion. But writing this post qualifies, even though it is obviously a social activity.
Or maybe it's not correct to characterize introverts as tired out by social interaction. Rather, they are tired out by particular modalities of social interaction. So perhaps there is a response possible to the argument of the preceding paragraph.