I have done some research to find out what has changed...
Basically since 1 week google has migrated the feedburner url to feedproxy.google.com as you can see on the picture below.
As I am pushing my feeds from feedburner to twitter via the API twitterfeed, it means the url that is appearing now on twitter is not including mastercom.over.blog.com but the rewritten url by google: feedproxy.google.com.
As a result, tweet meme is not able to index this feedproxy.google.com as a tweet for mastercom.over.blog.com...
So what is the solution to be sure tweetmeme continue to index your domain url?
The temporary solution I hav e found it to push my traditionnal RSS url without using the feedburner service.
Let's see if tweetmeme or google find a way to improve that.