If you need to ask a question create a message and notify person who needs to answer by email. Why do you need to introduce completely new object in the system when existing one can do the trick and give you more advantages (you can ask more than one person for an answer, attach files, discuss the answer)?
Logically Questions are the same as tasks except that they have a second description field which is used to stor the answer.
Questions can be asked in any direction (client, company, members...) within the project and can belong to task lists and milestones just like tasks.
Would anyone else like this feature?
Mat