BuddyPress.org

There are other platforms and have tried a few myself. As new as the bp platform is, it is by far the quickest out of the box that enables much of what you need already (together with wpmu). However other platform might offer more fine grained control, but it comes with a hefty learning curve as the platform is simply more complex. The upside to bp’s less complex architecture makes it also easier to develop for.

I’ll see if I can give some input on your requirements.

The main feature is an easy and somewhat restrictive way to post content. The only thing girls can publish is pictures of outfits, and then tag the clothes (describe, tag, categorize…).

It looks like you need a custom content type that omits the post message. Flutter allows you to create a specific post type. I haven’t tried it with wpmu. There is also a wpmu plugin called ‘toggle_meta_boxes’ which allows you to hide unneeded post boxes to make it super easy for your users to just upload content.

We want to have some level of control here. BTW not all users can upload content.

Since you only have one subject users post on I would recommend NOT giving every user a blog at sign up, but just let them post to the main blog. Keeps you in control over categories, tags, etc. Plus it lets you control the user level. I however you do want to give users a blog there are wpmu plugins which allow you to set blog defaults like categories, predefined pages and posts and such. Also you can make new blog users have an editor role rather than an admin role if you want to control what they can or can not do.

The content published by everyone goes to the main page, same of today.

This is done by buddypress through widgets or even custom loops if you are adventurous.

No problem there.

People con vote their fabs.

I haven’t looked at this, but I imagine there would be a wp plugin which would let users vote on posts. If you can find a vote plugin that serves an RSS feed you could pull that into the bp user profile. EVen link it to the activity stream with a small custom plugin.

When user is logged in, she sees the content of the girls she is following (not pictures of everyone, just pictures of the ones that inspire the user).

In bp through making friends with other users you can follow the activity of your friends only. At the moment the activity stream is text only, afaik, but I think images in the activity stream is in the pipeline?

User profile is built by the outfits she publishes

The profile page shows the latest activity, blog posts, wire messages, etc. of the profiles user.

and the outfits she favorites.

This is the most dificult part, since I haven’t looked into it. Assuming you can find a good vote/favorite plugin it should be doable.

You can search for/discover/subscribe to trends, types of clothes, styles, colors, people…

This is where bp shines as the search is very well done. Combine it with bp_contents plugin which allows your users to tag themselve, groups, blog and add categories…your archiving possibilities are endless.

Some pitfalls (already mentioned):

Privacy controls, inappropriate content flagging (is coming in 1.1 though), it is still not an out of the box solution (however for you requirements there is none that I can think of).

There are still even other approaches when I think about it, I would recommend wp and bp in a heartbeat. Especially since the backend of both are really solid. Plugins are installed and upgraded easily. It is a widely supported and growing platform and would not hesitate to recommend it to you.

I hope this helps a little bit.