One simple word, transparency!
When I go to Kred I get a first class user interface that shows all of my “shares” and the interactions they received – this is hands down the best feature I love about the site. Klout attempted this with “Your Moments” but its flaky and never seems up to date.
The second best feature is the fact I can see how my Kred score is calculated on my points page. I can learn what gets more points and for what reasons. Once again, I share and share and share and see what value the different shares bring by what interactions have taken place on them.