Is blk0001.dat the same everywhere?

[fghj]

I felt the urge to open terminal write sha512sum blk0001.dat press return and post what came out:
d7089979fb4acd27754a9900c62dbb1d4551c4eb8f17d9fdd1160799eb2060448a45dc9aa7191a8 8de8fc12a238057c2c5b065588fca7c90c739975a5e6826ea
I know answer is probably out there somewhere but I'm noob, so I'm gonna try to waste other peoples time.

[theymos]

No. Orphan blocks (blocks not in the main chain) are also stored there, and each node is likely to have a different set of orphan blocks.

[casascius]

Each person who downloads the block chain from scratch should however get an identical (hash-wise) blk0001.dat from now on though, right?  (I believe so based on my understanding, but my understanding is only as others have explained to me how it works).

If correct, this would be because the network is making no effort to keep the orphaned blocks in circulation.

[theymos]

Each person who downloads the block chain from scratch should however get an identical (hash-wise) blk0001.dat from now on though, right?

That seems likely. I'm not sure that blocks are guaranteed to be ordered sequentially in blk0001.dat, though, or that extra data isn't added.

[fghj]

I suppose there is some protection from receiving massive amounts of fake blocks from 2009 before getting normal blockchain.
Attacker with 1 GPU could make many GB of early orphans.