Similar to how you tag friends on Facebook and instagram, i suggest that rescreatu users should be able to tag other users in forum posts. This will enable users to see specific posts in a thread instead of subscribing to the whole thread.
In my case, many times I post on a thread and don't subscribe because I don't want to get an alert every time another users posts about something totally unrelated to what I am asking or posting about. Being able to tag a user in a post will allow users who are reluctant to subscribe to threads other than their own to only get alerts about specific posts which specifically have something to with them.
It is also a great way for a thread owner/shopkeeper to directly get in contact with users who have asked about an item or pet for sale.
I understand that some users will abuse this feature to get people to view their sales thread by tagging hundreds of users at a time. To dodge this, I also suggest that along with the tagging feature, a monitor be placed to disable users from doing just that. Staff members will be able to view posts which users have been tagged in and assure that users are not abusing the ability to tag users. If a user is found to be abusing it, the staff will issue a warning or alert the user of their abuse.
All in all, tagging will be a great feature that will enable users to only get alerts about posts that involve them and will allow shop owners to directly contact specific users.
:D