Currently, the SIG is working on the creation of Sourceforge tickets on several issues, as outlined in the report from the last SIG meeting.
The SIG runs a mailing list on this topic. To join, send a message to tei-ontology-sig-request@lists.sourceforge.net with the word SUBSCRIBE in the header or the body of the email.
The SIG also has a wiki. Currently, it is mainly of historical interest, but hopefully, it will be more actively used in the future.