I’m seeing the Tweet button along with the other social networking sharing buttons at the end of your posts using Firefox 12. Please try clearing your browser cache and cookies and then viewing your blog again.
Which verion of Chrome are you running? If you don’t know click here to find out > http://whatsmyuseragent.com/
I’m using Firefox 13 and can see all the sharing buttons. You may be right about this being a Chrome issue but I don’t run Chrome so I can’t test this. I’ve flagged this thread for Staff attention.