So I am my coworker have a differing opinion on social networking sites.

[belocally]

One of us says to join one or two, Linkedin being one of them and just work those. The other says to build profiles on multiple pages - everything from Merchant Circle to  fastpitch , essentially any and all, and not worry about activity level, just get the link. What are your thoughts? Which approve will result in more effective optimization for clients?

[ShaMenz]

Hi Brenan,

Social is worthless if it is not, well, Social!

The most important facet of using social media is building authority and/or recognition in your space. This kind of authority brings a raft of benefits, not the least of which is the fact that people will want to share what you share...

At a minimum I would pick the two that "work" best for the individual (or company they represent), and start participating in those in a meaningful way. If that works out, then try adding another and see if it also works for you. How many you can realistically manage to make a real contribution to will become clear over time.

My personal view is that a profile that looks like it has been deserted is more likely to do harm to your reputation than good.

Cyrus talked about managing profiles as part of a link building strategy in a blog post just last night. There is also some discussion relevant to your question in the comments on that post. Of course, there are some directories in the SEOmoz resource list that fill the bill for your co-worker too

In short, give yourself a big thumbs up on this one and send your co-worker a link to the post as well!

Sha

[RyanKent]

I would recommend the middle road. Grab all social networking IDs related to your site. Grab the id's for facebook, twitter, linkedin, stumbleupon, digg and all other popular social networks with your brand or site name. The reason is simple. You want to control those names and not allow someone else to do such. If you think "well, I don't use MySpace so I don't care about that one" imagine what is someone else can do if they controlled the id and shared information with it.

Once you have the id's, then the discussion with your coworker comes into play. I would recommend building the profile on each site. It is simple and fast to do. It also may expose your site to people who otherwise may not find it.

After the profile is created, then Syed's points should be considered. The value of your profiles with these various networks increase with your level of activity. Simply creating the profile does offer some value, but not much.

[Syed1]

Just creating zillions of social profiles for a link isn't going to help much. In fact there are many automated software, the borderline spammy ones, that does it for you but those links don't add value and if you domain is not of high authority, it could potentially even cause a dent on the domain 'trust' level.

If I were you, I would focus on few in the beginning - Twitter, FB, Linked & Youtube or other one depending on your niche, and add couple of more social networks every month, so you are building on social signals without quickly thinning out on the activity levels for each. You don't have to be very active in all networks, but have more than just couple of social profiles is good. Digg and SU is definitely worth considering because of the traffic they can send to you along with the longer term social juice for SEO