I noticed that even post penguin, a lot of members still have triple or more exact anchor text signatures...this is the best way to get hit by Google Penguin...
To be safe the recommendations are to do this way for signatures:
some text and then link a keyword that is not a money keyword for example this
and then at the end the URL like this http://marketingforums.net/newthread...newthread&f=47
You also need to add variations of your domain name like:
Home | wexample.com