If you click View My Sales Opportunities from the Dashboard page of MC Trade, you'll jump down to the bottom of your browser dashboard to see all open Sales Opportunities, that are assigned specifically to you.
In the "Last Contacted Date" column, you'll see the date of the last Contact record that you personally recorded on the profile for that row. If no date is displayed, you have never recorded a Contact for that profile.
In the Actions dropdown, you can edit the Sales Opportunity (or delete it), or you can Add a Contact to the profile straight from this screen. The normal Contact form appears, and that contact will appear on the Contact History for the profile and update your "Last Contacted Date."
You can also click on the profile name to navigate to and edit that profile.