Continuing the discussion from Google Search Results are not good:
The “similar” topics popup seems to only be strongly based on the topic title you choose, but it only pops up after you start composing the message.
It shouldn’t require both the topic title and the message body. Either should be sufficient to start telling you what you’re writing may be similar to something else.
If you start with a title, it’d be better if it popped up as you’re typing the topic title, like it does in the search box. That way you can hop around to those topics to see if they really are similar before you start typing your message…
If you start with writing the body, it should pop up while you’re composing (some folks might not pick their carefully worded title until they have their full idea composed). Currently it ignores the contents of the message body altogether.