Sadly, a lot of people don't seem to grasp the concept of a "Thread" of discussion and will post replies as a new thread instead of a reply in the existing thread.
eg: http://www.keil.com/forum/18111/
Therefore my suggestion is to remove the 'Start a Thread' option from within a thread and, possibly, replace it with 'Reply'
Thus it would only be possible to start a new thread from Threads list - and would not be possible to "accidentally" start one instead of replying.
Magnificent idea!
Another example: http://www.keil.com/forum/18113/
http://www.keil.com/forum/18151/
Yes a good idea.
Seldom does one fail so totally to grasp the threading concept:
http://www.keil.com/forum/18626
http://www.keil.com/forum/18623
http://www.keil.com/forum/18614
http://www.keil.com/forum/18568/
Not quite up to the previous entry, but a strong contender:
http://www.keil.com/forum/19209
http://www.keil.com/forum/19207
http://www.keil.com/forum/19203