Please check, why trackbacks for posted arXiv articles don't appear on http://arxiv.org/tb/recent
1) Understand the trackback mechanism in BibSonomy that is described here: https://www.kde.cs.uni-kassel.de/mediawiki/index.php?title=Bibsonomy:Trackback
2) Take the Java classes that implement the Trackback autodiscovery in BibSonomy and write JUnit test case that tests if the trackback URL can be discovered in an article from arXiv, etc. http://arxiv.org/abs/adap-org/9906003
3) If the test fails, find out why autodiscovery does not work and talk to Robert
(4) Fix the autodiscovery)
5) Check, if there are other reasons why it fails, discuss with Robert, fix.