[exim] Disconnections in Log File

I'm getting all sorts of messages like this in my exim/mainlog file:

2007-04-07 17:06:36 unexpected disconnection while reading SMTP command from
30-227.187-72.tampabay.res.rr.com (localhost.localdomain) [72.187.227.30]
2007-04-07 17:06:35 H=(localhost.localdomain) [69.182.14.70] incomplete
transaction (connection lost) from <kaskew@???>
2007-04-07 17:06:35 unexpected disconnection while reading SMTP command from
(localhost.localdomain) [69.182.14.70]
2007-04-07 17:06:35 H=(218.2.109.50) [218.2.109.50] incomplete transaction
(connection lost) from <hqemillinery@???>
2007-04-07 17:06:35 H=82-39-157-144.cable.ubr01.gate.blueyonder.co.uk
(localhost.localdomain) [82.39.157.144] F=<laimee@???> rejected RCPT
<cochran@???>:

What does this mean? I'm relatively new to exim and have never see these
kinds of messages before with sendmail or qmail.

Thanks!