Tomorrow from 5 to 10pm at The Sycamore in San Francisco some friends and I will be accepting bitcoin payment for draft beer.

Details at http://beercoin.net/

Yet blockchain.info claims it was! Interesting. Do they just attribute blocks by the IP address that first relayed it to them?

Why? Is there any reason pool members should be expected to have well-synchronized clocks?

FWIW, these two blocks just recently mined by Deepbit also have out-of-order timestamps:
http://blockchain.info/block-height/171974
http://blockchain.info/block-height/171975

as do lots of other blocks, I'm now realizing.

And, 3 of the 5 empty blocks so far today have come from these two new IPs:

http://blockchain.info/ip-address/95.172.9.82 (2 empty blocks today)
http://blockchain.info/ip-address/85.127.161.5 (1 empty block today, 1 on March 14, and 1 non-empty block on March 13)

The other two came from the Deepbit mining pool, which also mined some empty blocks yesterday.

Two other IPs have relayed new empty blocks (and have not relayed non-empty blocks) in recent days, including another two in a row yesterday:

http://blockchain.info/block-height/171806 (relayed by 188.127.227.12)
http://blockchain.info/block-height/171807 (relayed by 213.171.43.151)

Here are blockchain.info's lists of transactions first relayed by each of the four IPs I've seen relaying new empty blocks recently:
http://blockchain.info/ip-address/88.6.216.9 (29 empty blocks between March 3 and March 7)
http://blockchain.info/ip-address/85.214.124.168 (74 empty blocks between March 15 and March 19)
http://blockchain.info/ip-address/213.171.43.151 (9 empty blocks between March 14 and March 19)
http://blockchain.info/ip-address/188.127.227.12 (6 empty blocks between March 16 and March 19)

All of these IPs have also relayed other transactions, which leads me to this theory: Perhaps these IPs are just regular bitcoin nodes, and are not related to the empty-block miner at all? They could just be relaying transactions and blocks for everyone, and the empty-block miner is merely choosing for some reason to always relay their work through this small set of nodes.

It would be easy enough to test this theory (or confirm its negative it, at least) by trying to relay some transactions through them, but I haven't done that. I did however confirm that two of them (85.214.124.168 and 213.171.43.151) are currently listening on the default bitcoin port (8333).

Also, to repeat my earlier question, could there be any significance to the out-of-order timestamps in blocks 171759 and 171760 other than indicating that the empty-block miner's nodes don't have synchronized clocks?

I joined this forum to discuss the mystery of the empty-block miner who presently appears to have ~15% of the hash power. I would like to contribute to the discussion at https://bitcointalk.org/index.php?topic=67634 starting with the posts I made in the newbie section at https://bitcointalk.org/index.php?topic=69340

Thanks.

I have a theory, given that all four IPs I mention above are relaying other transactions besides the empty blocks:

The IPs in question could be regular innocent bitcoin nodes, not controlled by the empty-block miner miner at all; they are just relaying transactions and blocks for anyone. The miner is just sending their blocks to this small number of IPs to be relayed to the rest of the network.

Could someone copy+paste this theory to the big thread for me? And can anyone tell me how long the newbie restriction on this forum lasts? edit: I posted to the whitelist request thread. w00t! I am whitelisted now.

No, I'm talking about the timestamp field which is part of the block, not the "received time" field which is just from blockchain.info's point of view. Blockexplorer.com also shows those two timestamps out of order:

https://blockexplorer.com/block/00000000000008729cb2580c281200c2c2296757def0d8b27f4b7b8a047d4d34
https://blockexplorer.com/block/00000000000000b480d06cbe1c462c76e8ca51587f4c37cf65651d5b47eccfae

In other news, two more IPs have been mining empty blocks in recent days, including two in a row a couple hours ago:

http://blockchain.info/block-height/171806 (relayed by 188.127.227.12)
http://blockchain.info/block-height/171807 (relayed by 213.171.43.151)

Here are blockchain.info's transactions relayed lists for all four of the IPs I've seen mining empty blocks recently:
http://blockchain.info/ip-address/88.6.216.9 (29 empty blocks between March 3 and March 7)
http://blockchain.info/ip-address/85.214.124.168 (62 empty blocks between March 12th and today)
http://blockchain.info/ip-address/213.171.43.151 (9 empty blocks between March 14th and today)
http://blockchain.info/ip-address/188.127.227.12 (6 empty blocks between March 16th and today)

If all four are the same entity, I think they have more than (edit: maybe not) 15% of the hash power now (the amount estimated by https://www.privateinternetaccess.com/blog/2012/03/bitcoin-war-the-first-real-threat-to-bitcoin/ ).

Also worth noting, these IPs are relaying new transactions too, aside from winning blocks.

Regarding the mystery miner being discussed in https://bitcointalk.org/index.php?topic=67634.200 ... (originally at 88.6.216.9 and now at 85.214.124.168):

A little while ago they mined four blocks in the space of 1 hour:

http://blockchain.info/block-height/171757
http://blockchain.info/block-height/171759
http://blockchain.info/block-height/171760
http://blockchain.info/block-height/171763

Interestingly, the timestamps on their two consecutive blocks 171759 (2012-03-18 19:31:32) and 171760 (2012-03-18 19:31:30) are out of order! This implies to me that either there are some shenanigans I don't understand the point of, or this is a botnet without good clock sync.

Can someone explain what the timestamp field is used for?

ps: someone who isn't limited to the newbie forum, please copy+paste this post to the myster miner thread. edit: thanks, Mushoz!