This from our fine friends at eMarketer. Here’s the requisite chart:

Passing the 50% mark is being touted as a major tipping point in the way that people consume content, but I think it’s just a big number that looks impressive. We passed the tipping point a long time ago – the number that indicates that is the nearly 75% of Internet users who have watched video online.

The incredible thing you must remember, before this becomes old news, is that most of that behaviour was spread virally by email and IM – first dozens, and then hundreds and eventually millions of people sharing links to cool videos with one another.