Hi Jan, hopefully this will help:
Just as you've been able to add your latest blog post to your profile so it shows up with your username at each post you make, now you can keep other members updated on what your latest Twitters are! Here's how to use the "My latest Twitter" feature (if you have a Twitter account: Don't worry, you don't need to update "Your latest Twitter" every time you make a tweet, that part will be done automatically. Click "Settings" on the top menu and then click "Edit Options" on the left menu, then scroll all the way down and find the field called "Twitter Username", enter your Twitter username and save the info. Your Twitter feed will update on the forums every hour and display next to your username with every post you make. This functions simultaneously with the My Latest Blog Post feature so you can have both at the same time!
From the
Virtual Assistant Forums FAQ
Thie field you're filling in just adds the URL to your profile page - use the instructions above to add your Twitter feed to your username.