tweets with the same status texts get the same id

[twibble]

when I send a tweet twice with the same status text the twitter api
returns for both messages the same id and the same time in created_at.
E.g.:

beast:~ thilo$ curl --trace-ascii out --basic -utwibbletest -
dstatus="foo" http://twitter.com/statuses/update.xml
Enter host password for user 'twibbletest':
<?xml version="1.0" encoding="UTF-8"?>
<status>
<created_at>Wed Mar 26 19:14:17 +0000 2008</created_at>
<id>777547650</id>
<text>foo</text>
<source>web</source>
<truncated>false</truncated>
<user>
<id>6450932</id>
<name>twibbletest</name>
<screen_name>twibbletest</screen_name>
<location>Hamburg, Germany</location>
<description>I am here just for testing purposes with my friend
twibble</description>
<profile_image_url>http://static.twitter.com/images/
default_profile_normal.png</profile_image_url>
<url></url>
<protected>true</protected>
</user>
</status>
beast:~ thilo$ curl --trace-ascii out --basic -utwibbletest -
dstatus="foo" http://twitter.com/statuses/update.xml
Enter host password for user 'twibbletest':
<?xml version="1.0" encoding="UTF-8"?>
<status>
<created_at>Wed Mar 26 19:14:17 +0000 2008</created_at>
<id>777547650</id>
<text>foo</text>
<source>web</source>
<truncated>false</truncated>
<user>
<id>6450932</id>
<name>twibbletest</name>
<screen_name>twibbletest</screen_name>
<location>Hamburg, Germany</location>
<description>I am here just for testing purposes with my friend
twibble</description>
<profile_image_url>http://static.twitter.com/images/
default_profile_normal.png</profile_image_url>
<url></url>
<protected>true</protected>
</user>
</status>

Is this the intended behaviour? Looks strange to me ...

Best,
@twibble

[Alex Payne]

Well, you're posting what our system considers to be a duplicate, so
we ignore the duplicate and hand you back your most recent status.
Would an error that you've posted a duplicate be more helpful?

--
Alex Payne
http://twitter.com/al3x

[twibble]

ah, ok, I didn't know that. When is a tweet considered to be a
duplicate of another? If it has the same status text from the same
user in a given time range? And yes, an error message would be great.
I was indeed wondering what was going on.
thx