For example, I’d like to know when anyone posts about henna. My husband would like to know about all Islam threads. Can I set up to get a message whenever that happens?
Sorry, no. You have to find threads first and then subscribe to them. If you want to find older threads, you can first try www.boardreader.com and include the search term straightdope in your search. Some people say that the search term “SDMB” also works.