I just finished creating my Plaxo account. It reminded me of when facebook first came out. Super basic, easy to navigate tabs and just a simple networking website. None of my friends appear to be on the site... it doesn't seem like it has picked up on having a huge number of members yet. In time :)
As far as LinkedIn goes I have had an account with virtually nothing in it for a while. I would like to continue to have it that way. There are tooo many people from work on there, and I would like to keep some distance from home and work. I feel like that relationship to being monitored/ accessible all the time needs to be a tad bit distant. That sounds pseudo bad but I need my space when not at work.