user516: Reddit/r/bitcoin is flooding with news that the Bitcoin blockchain has forked, in that versions 0.7 and 0.8 are accepting different blockchains. What does this mean for the users?

user516: Gavin Andreson has tweeted this:
https://twitter.com/gavinandresen/status/311290936527298561
The bitcointalk post linked by Gavin is a post by Peter Wuille, which says this:
Hello everyone,
there is an emergency right now: the block chain has split between 0.7+earlier and 0.8 nodes. I'll explain the reasons in a minute, but this is what you need to know now:

After a discussion on #bitcoin-dev, it seems trying to get everyone on the old chain again is the least risky solution.
If you're a miner, please do not mine on 0.8 code. Stop, or switch back to 0.7. BTCGuild is switching to 0.7, so the old chain will get a majority hash rate soon.
If you're a merchant: please stop processing transactions until the chains converge.
If you're on 0.7 or older, the client will likely tell you that you need to upgrade. Do not follow this advise - the warning should go away as soon as the old chain catches up.
If you are not a merchant or a miner, don't worry.

An announcement has also been made at bitcoin.org.

516: <p><a href="http://www.reddit.com/r/bitcoin">Reddit/r/bitcoin</a> is flooding with news that the Bitcoin blockchain has forked, in that versions 0.7 and 0.8 are accepting different blockchains. What does this mean for the users?</p>
 516: <p>Gavin Andreson has tweeted this:
<a href="https://twitter.com/gavinandresen/status/311290936527298561">https://twitter.com/gavinandresen/status/311290936527298561</a></p>

<p>The bitcointalk post linked by Gavin is a post by Peter Wuille, which says this:</p>

<p><em>Hello everyone,</em></p>

<p><em>there is an emergency right now: the block chain has split between 0.7+earlier and 0.8 nodes. I'll explain the reasons in a minute, but this is what you need to know now:</em></p>

<ul>
<li><em>After a discussion on #bitcoin-dev, it seems trying to get everyone on the old chain again is the least risky solution.</em></li>
<li><em>If you're a miner, please do not mine on 0.8 code. Stop, or switch back to 0.7. BTCGuild is switching to 0.7, so the old chain will get a majority hash rate soon.</em></li>
<li><em>If you're a merchant: please stop processing transactions until the chains converge.</em></li>
<li><em>If you're on 0.7 or older, the client will likely tell you that you need to upgrade. Do not follow this advise - the warning should go away as soon as the old chain catches up.</em></li>
<li><em>If you are not a merchant or a miner, don't worry.</em></li>
</ul>

<p><a href="http://bitcoin.org/chainfork.html">An announcement has also been made at bitcoin.org</a>.</p>
