Regexing it up with IIS re-write module

I am developing a profile-based web application where each user is assigned there own url through their username & iis rewrite mod's magic. A typical user's profile url would be http://www.mymark.com/mike

Each user is also created a blog in a multi-user wordpress installation. The wordpress url would look like this: http://www.mymark.com/blog/mike

I am trying to use the rewrite module to create more canonical urls for the user (http://www.mymark.com/mike/blog), an开发者_运维知识库d have tried several regex variations that I have created through RegExr(a regex generation tool) and come up with this as the pattern to match (www.|)mymark.com/([^/]+)/blog but haven't had any success so far. What am I doing wrong here?

Here is a screen shot of my re-write rule:

The entire host name (mymark.com) is not part of the URL, so you should not enter that as part of the Pattern. To make sure you easily figure it out, make sure to use Failed Request Tracing to extract the exact pattern that you should enter there: http://learn.iis.net/page.aspx/467/using-failed-request-tracing-to-trace-rewrite-rules/

but its probably going to be something like: (^/])*/blog