One of the reasons why social networking is great, it's because you can access your pages from all over the world.
If I am in a internet point in Timbuktu I can still check my myspace and facebooks accounts.
What's really bad about net4mac is that you need to have an application installed on your Mac to access its features.
This means that you can't use your browser's favourite features and extensions, you can't open links in new tabs, and you are limited by the choices of the application's programmers.
Also, if I had to keep an application open for every service I use, soon it would be quite hard to work on my Mac. That's why I use Adium for all my instant messaging services, and not iChat, MSN, a Jabber client, ICQ at the same time.
So, I really can't understand and support the choice made by the net4mac guys: I actually find it's quite weird, expecially when you think that all the application does is showing web pages within its interface!
Net4mac is a promising service, but the way it is right now just doesn't work for me.