If you don't have a blog, you can still participate! There are two other ways for you to participate. (You can of course participate in ALL three ways if you'd like, you go getter you.)
1)The kind folks at Go Chic or Go Home have created a special 30 for 30 page, so that you can participate.
If you aren't a member: http://gochicorgohome.com/pub/welcome-kendi-everyday-readers
If you are a member: http://gochicorgohome.com/explore/members30
2) Flickr! Just add your outfits to the group: http://www.flickr.com/groups/30for30/