user1745: I have 3 graphics cards mining with poclbm (no external pool) and they all have pretty much the same output: 
MYSERVER:MYPORT [141.642 MH/s (~0 MH/s)] [Rej: 0/0 (0.00%)]

what does the "~0 MH/s" mean?

user2306: From the poclbm source code, Switch.py line 219:
say_quiet('%s[%.03f MH/s (~%d MH/s)] [Rej: %d/%d (%.02f%%)]', (if_else(verbose, miner.id()+' ', '') , rate, round(estimated_rate), rejected_shares, total_shares, float(rejected_shares) * 100 / total_shares_estimator))

It's estimated_rate.  
And how estimated_rate that found, you ask?
I tried looking at the source, but that didn't really clear things up.
self.estimated_rate = Decimal(new_accept) * (targetQ) / min(int(now - self.start_time), self.options.estimate) / 1000
self.estimated_rate = Decimal(self.estimated_rate) / 1000

I eventually found this discussion on bitcointalk. It states that the estimated rate is based on how many shares are submitted to the pool. I don't know what it's supposed to display if you're not using a pool.

1745: <p>I have 3 graphics cards mining with poclbm (no external pool) and they all have pretty much the same output: </p>

<pre><code>MYSERVER:MYPORT [141.642 MH/s (~0 MH/s)] [Rej: 0/0 (0.00%)]
</code></pre>

<p>what does the "~0 MH/s" mean?</p>
 2306: <p>From the <a href="https://github.com/m0mchil/poclbm" rel="nofollow">poclbm source code</a>, Switch.py <a href="https://github.com/m0mchil/poclbm/blob/master/Switch.py#L219" rel="nofollow">line 219</a>:</p>

<pre><code>say_quiet('%s[%.03f MH/s (~%d MH/s)] [Rej: %d/%d (%.02f%%)]', (if_else(verbose, miner.id()+' ', '') , rate, round(estimated_rate), rejected_shares, total_shares, float(rejected_shares) * 100 / total_shares_estimator))
</code></pre>

<p>It's <code>estimated_rate</code>.  </p>

<p>And how <code>estimated_rate</code> that found, you ask?<br>
I tried looking at the source, but that didn't really clear things up.</p>

<pre><code>self.estimated_rate = Decimal(new_accept) * (targetQ) / min(int(now - self.start_time), self.options.estimate) / 1000
self.estimated_rate = Decimal(self.estimated_rate) / 1000
</code></pre>

<p>I eventually found <a href="https://bitcointalk.org/index.php?topic=34190.0" rel="nofollow">this discussion on bitcointalk</a>. It states that the estimated rate is based on how many shares are submitted to the pool. I don't know what it's supposed to display if you're not using a pool.</p>
