I'm a member of the Linkedin professional networking group. I've found it to be quite helpful in making connections with new friends and colleagues around the world. While most of the features of the network are available and visible on the web to members only, Linkedin recently added a feature whereby the internal Linkedin "member profile" can be displayed publicly on the web. Here's the public view of my own Linkedin profile:
I like the ability to select which segments of the profile will be displayed - that's a nice touch. For example, for public display I selected things that reflect my current activities and not my entire employment history - I leave that for my about me page her and my resume.
I don't think I'll be adding the above link to my standard email signature; I alreay include my blog address now (www.ddmcd.com) and I think I'll leave it at that.
The only thing which gave me pause about this public Linkedin profile was the fact that the profile and my blog have such different graphic design and layout features that it is clear that the two are different sites and using the above link will take people away from my pages here. I realize that's the simple fact but I actually wouldn't mind the ability to embed the profile within one of my pages with the "look and feel" of my existing design.
A related issue is that I don't display ads on my blog -- if I were to display the Profile within my blog I would want the ability to strip out the ads.