Since the choice is included within the subject line you will be able to search the receiving mail-in database view for the keyword (choice) and quickly count the responses.
With your Inbox open, click on Tools right above the list of your emails. Click on Mail Rules, then New Rule. In the Create Condition dropdown, you can choose Subject and type in the subject you want to filter to your folder you choose in the Specify Action area.
Sorry, there is nothing as simple as in Outlook. The best description of the process to create a voting button is on http://www.alanlepofsky.net/alepofsky/alanblog.nsf/dx/voting. (Depending upon your access rights, you may have to click Add Action and choose @Function Formula before pasting your code.)
Combine this with the auto-routing for a relatively easy vote counting, especially if the question is a simple yes/no. Have yes answers go to one folder, no answers to another. When it is counting time, CTRL A to select all the answers in a folder and the number selected will show on the lower left.