Mercury goes retrograde on September 7. It will be retrograde in Virgo and Libra. What does this mean?

There is an excellent article on this Mercury retrograde here - http://www.psychicpower.com/articles/Mercury-Retrograde-2009-September-7---September-29.aspx

It is interesting that while this retrograde does seem to be affecting some people, it has not really affected me (knock on wood!). Maybe this is because I was on the path of making changes anyway.

Do different mercury retrogrades mean different things? For example, does it depend on the signs of that particular retrograde period?

Yes...that is a great article!