This is something I brought up before and @Martok answered my questions awesomely, and I agreed with him that the time shouldn't jump forward or backward. If you did something yesterday at 11:30 PM, then you did something yesterday at 11:30 PM regardless if DST took place the following day. Forum software that automatically changes it to yesterday at 10:30 PM (if minus one hour) or today at 12:30 AM (if plus one hour) is incorrect. However, at the same time, when we go back an hour, there are going to be many oddities.
For example, Eastern time just went back an hour a few minutes ago, and to test something, I temporarily changed my time zone to Eastern on another forum (could have just viewed the forum as a guest, but meh). This person has Eastern time, but...
Local Time: 1:04 AM
Last Activity: 30 minutes ago at 1:34 AM