Social Media Down

Is it me or is promoting a blog/site on social media becoming not worth it?

i have recently joined; technorati, mixx.com (chime-in now?), digg, and delicious.

Technorati is alright, they autoupdate my posts and im slowly gaining authority so im ok with them for now.

Mixx.com or chime-in. This site stink, imo, unless im not using it right. I joined several communities that match my blog, but when it comes time to chime about it, i can't select them. I have to go to each community and post in there. Not only that but no one uses the site. I think across like the 100 communities I looked at maybe only 2000 users?

digg.com - omg spam city. under the sports newswire all I see all day is spam spam spam decent digg spam spam. then once you do post something interesting it gets buried or ignored. and i swear if i see another thing from the huffington post im going to freak.

delicious - no way to get promoted to the top in this from what I can see. Created a sports stack, post like 50-50 my stuff and stuff from mlb and nfl and the stack has only had 17 views in 5 days? come on.

idk if im just not using them right or what. what is everyone else's experience with these sites and do you have any suggestions, beside facebook and twitter for me to check out.

thanks.