If you're looking for the new round start/new lineups post, it is here.
I've noticed that a few people on "standard" teams have chosen to post their shiritori on ao3 and just link to it on writetomyheart with the last line for easy reference. This is absolutely good to go. (And has definitely happened in the past as well.)
I just wanted to clarify that, now that we have an "official" ao3 shiritori collection, if you're posting your shiritori fic on ao3 only and just linking it to writetomyheart, please do include it in the shiritori or sonic_shiritori collection, as applicable.
However, I'll restate that this is only if you're only posting your shiritori fic on ao3. If you're crossposting a shiritori fic that was originally posted on writetomyheart, then adding it to the "official" collection is completely optional.
Drop a comment if you have any questions!