4 random suggestions
1) Select some text in a posters message and a "quote" button appears, click quote and this triggers the beginnings of a comment with the selected text already quoted. Nice when someone wants to address a specific passage of text in a question.
2) auto complete names, for example type @part_of_a_member's_name while answering a question and it will bring up a list of member names.
3) When composing a new message, it would be nice if the system would encourage a quick search but cleverly considering the title and revealing a list of potentially already asked questions. This could help avoid repetition.
4) Tags — encourage use of tags by adding a field for the same, this could really correlate a lot of things together.
Thanks for considering.