I've had a [mini-discussion on the topic](https://stackoverflow.com/a/9265490/58463) in another thread, and would like to have people's input on the "bad" sides of subjects.

People who frequent the RX forum know that [E.Meijer does not like Subjects](http://social.msdn.microsoft.com/Forums/en-US/rx/thread/bbf87eea-6a17-4920-96d7-2131e397a234). While I have a deepest respect to RX creator's opinion, I have been using Subjects quite extensively in multiple projects for a couple of years and haven't had any architectural problem or a bug because of them.

The only "pitfall" with Subjects I can name is that they are not "reusable" - after you have completed an observable on a Subject, you need to re-instantiate it, before new subscribers can receive events from it. 

"Code smell" and "Don't like them" need to be supported by "pragmatic" examples - can you bring to our attention possible situations when using a Subject can lead to a bug or a problem? Or maybe you think they are easy and harmless altogether - then try to define an area where they are to be used.