Osmarender currently adds the output listed below to the svg files that it generates.  I don't think the plain text Copyright line is correct though.  It really should be something like "Copyright 2007 OpenStreetMap contributors".  And the rdf stuff is way too much to return in every single api call.
<br><br>Perhaps individual node, segment and way requests should have a very abbreviated notice and the bbox request have something more comprehensive.<br><br>As a specific requirement it would be very useful to have the date/time of the request provided in the response, so that an accurate date can be shown on copyright notices in documents that are derived from the data (like Osmarender's svg output).
<br><br><!--<br><br>    Copyright (c) 2007 OpenStreetMap<br>    <a href="http://www.openstreetmap.org">www.openstreetmap.org</a><br>    This work is licensed under the<br>    Creative Commons Attribution-ShareAlike 2.0
 License.<br>    <a href="http://creativecommons.org/licenses/by-sa/2.0/">http://creativecommons.org/licenses/by-sa/2.0/</a><br><br>--><br><metadata id="metadata"><br><rdf:RDF xmlns="<a href="http://web.resource.org/cc/">
http://web.resource.org/cc/</a>"><br><cc:Work rdf:about=""><br><cc:license rdf:resource="<a href="http://creativecommons.org/licenses/by-sa/2.0/">http://creativecommons.org/licenses/by-sa/2.0/
</a>"/><br><dc:format>image/svg+xml</dc:format><br><dc:type rdf:resource="<a href="http://purl.org/dc/dcmitype/StillImage">http://purl.org/dc/dcmitype/StillImage</a>"/><br><dc:title/>
<br><dc:date>2007-07-03</dc:date><br><dc:source><a href="http://www.openstreetmap.org/">http://www.openstreetmap.org/</a></dc:source><br></cc:Work><br><cc:License rdf:about="<a href="http://creativecommons.org/licenses/by-sa/2.0/">
http://creativecommons.org/licenses/by-sa/2.0/</a>"><br><cc:permits rdf:resource="<a href="http://web.resource.org/cc/Reproduction">http://web.resource.org/cc/Reproduction</a>"/><br><cc:permits rdf:resource="
<a href="http://web.resource.org/cc/Distribution">http://web.resource.org/cc/Distribution</a>"/><br><cc:permits rdf:resource="<a href="http://web.resource.org/cc/DerivativeWorks">http://web.resource.org/cc/DerivativeWorks
</a>"/><br><cc:requires rdf:resource="<a href="http://web.resource.org/cc/Notice">http://web.resource.org/cc/Notice</a>"/><br><cc:requires rdf:resource="<a href="http://web.resource.org/cc/Attribution">
http://web.resource.org/cc/Attribution</a>"/><br><cc:requires rdf:resource="<a href="http://web.resource.org/cc/ShareAlike">http://web.resource.org/cc/ShareAlike</a>"/><br></cc:License><br></rdf:RDF>
<br></metadata><br><br><div><span class="gmail_quote">On 7/4/07, <b class="gmail_sendername">Tom Hughes</b> <<a href="mailto:tom@compton.nu">tom@compton.nu</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
In message <!&!AAAAAAAAAAAuAAAAAAAAAOKaD4mR3JBOrEpRon92nMgBANp/H2q5kHFIvKMsnZiQaZAAAAABxJAAABAAAADEVN6ZBsbXSZO3eDQKLhqLAQAAAAA=@<a href="http://blueyonder.co.uk">blueyonder.co.uk</a>><br>        Andy Robinson <
<a href="mailto:Andy_J_Robinson@blueyonder.co.uk">Andy_J_Robinson@blueyonder.co.uk</a>> wrote:<br><br>> +1 for that. We really ought to get the API doling out the licence stuff<br>> asap. Sorry I'm not sending a patch that does so :-(
<br><br>I can make the change if somebody lets me know what it needs to say.<br><br>Tom<br><br>--<br>Tom Hughes (<a href="mailto:tom@compton.nu">tom@compton.nu</a>)<br><a href="http://www.compton.nu/">http://www.compton.nu/
</a><br><br>_______________________________________________<br>talk mailing list<br><a href="mailto:talk@openstreetmap.org">talk@openstreetmap.org</a><br><a href="http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk">
http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk</a><br></blockquote></div><br>