Link building is becoming more and more of a challenge these days for websites, especially with the popularity of social networking sites, blogs, consumer-generated content, etc. I'm curious if any of you SEOs out there propose a link building strategy to your clients that include these type of sites and do you recommend they do the link building on their own? Or do you offer to do it for them? I can understand submitting a client's site to directories, contacting webmasters for links, etc. But how do you go about getting the attention of these other sites (besides the natural way - good content)? Do you contact the bloggers, etc. and tell them about some great product or service your client offers? Or do you have your client deal directly with these sites?