Implement Trackback

XWiki should support trackback:

http://www.sixapart.com/pronet/docs/trackback_spec

A minimal spec could be:

• support XWiki being pinged by other applications limited to pages representing a blog article and upgrading blog sheets and macros to display pings correctly
• support XWiki pinging a trackback enabled application, presumably by a new field in the ArticleClassSheet for optionally entering a trackback url

supplementary features:

• user interface for displaying and deleting trackbacks on a wiki page
• user interface for listing and deleting pings througout a wiki or a space
• latest pings in space or in wiki panel
• etc...
  It may be interesting to envision this to go beyond just a blog article, to any wiki page.

I will attach a small demo that stores pings to any wiki page in a TrackbackClass.

Thanks to Frank Häfemeler for raising this issue.