I do the same thing as you do -- concentrate on less networking platforms -- for best results.
One thing I said over and over again (for I believe in it), is that every networker needs to set objectives for networking and measurement criteria (to see how effective this activity is).
Anyhow, this is how I view a few different networking platforms I tried so far:
is a perfect place to meet all the HR people in the World (just kidding! but it's getting close to that) and network with some of the marketing professionals and business owners from a wide range of industries. Unless you pay for the subscription, reaching people through LinkedIn can be cumbersome. Nevertheless, this is NOT a conversational platform -- it's very dry and therefore it requires a low level of emotional involvement
-- much friendlier than LinkedIn, a mixture between friends and business, with tons of applications (some are really annoying) -- you can easily reach people through this network and in my view it requires a medium level of emotional involvement. I recently met with the Facebook Director for Illinois and I found out, to my surprise, that 35+ is the core user age group. Next month I'll join the core Facebook crowd!
-- is a very warm, full of personality, excellent navigation, diverse and engaging. The little recent hiccups are quite normal for a website which reaches critical mass and continues to grow.
-- just another LinkedIn, but with more freedom to contact people. Not hihgly engaging, but from time to time I get invites and notes from Plaxo members in my personal inbox.
-- I'll take a look at it -- I have heard of it but I did not try it yet.
- I tried this networking group for a while but it did not work for me: too cumbersome, time consuming, meetings are help in person every week, no professional guidance is being offered by the group leaders, lots of restrictions, very off-line in an on-line digital world, in a word: an unnecessary headache. Nevertheless, the intent of this group is very good but the way they put it into practice raises serious question marks.
-- stay tuned for the summer launch!