Yesterday we covered comScore’s estimate that 132 million Americans, or 75 percent of U.S. internet users, viewed streaming video online in May. That was distributed across 8.3 billion video streams.

We should also note that Nielsen put out some numbers of its own, related to a report trying to prove that traditional television viewing is not being replaced by by internet television viewing. Nielsen’s estimates are a bit smaller, but it’s limiting itself to U.S. broadband users rather than just U.S. internet users.

Nielsen said 81 million people, or 63 percent of its estimated 129 million broadband users, watched broadband video at home or at work in March. That’s up 16 percent from 70 million in September 2006.

The most direct comparison — because really, broadband seems like a necessity for web video — is Nielsen’s 63 percent to comScore’s 75 percent number. That’s a disparity that we can’t really duke out on their behalf.

Some other related numbers are out there too. ABI Research recently said there are 300 worldwide internet video consumers. It projects that number growing to 1 billion by 2012.

iSuppli sees professionally produced video driving growth, with 3.7 billion streams in 2006 set to grow to 79.3 billion streams worldwide in 2011. More on that later.