Hi 
 I find an error in the galaxy wiki page.
 please see "Admin/Datatypes/Adding Datatypes" which URL is 
 http://wiki.g2.bx.psu.edu/Admin/Datatypes/Adding%20Datatypes

<datatype extension="foo" type="galaxy.datatypes.tabular.Foobar" display_in_upload="true"/>
<sniffer type="galaxy.datatypes.tabular.Foobar"/>

I guess there should be ":" between "tbular" and "Foobar" not "."