Depends on the topic of your site I guess. I would say without a doubt that in the vast majority of cases, this type of traffic does not aid in achieving conversions.

Well that's reason enough to avoid it don't you think?

I'm new to social networks.

I thought social networks where groups of people interested in the same things.

Suppose you sell mufflers for 70's cars. Would you not want to be active in social networks where people with these cars were also active?

One word "TRASH"

Depends on what you are selling. Some sites do very well with social traffic, like those selling services that compliment social sites... ;-)

Those who go to social networks usually go to talk about themselves and their navels. They do not usually enter in "search mode" and are therefore far less likely to look at ads. At this very moment advertisers are trying to figure out how to handle this contradiction in order to tap into the huge traffic. Notice that Twitter has not been monetized as of yet, and I don't think Facebook is doing that well.

I have not seen any convincing data yet which indicates that social networks of any kind are doing well in terms of revenue--the model(s) has not been developed. Surely they will, but it will require enormous creativity--and I never doubt the American genius for selling product. TV was invented only to sell soap!

Even those with social networks who sell services which compliment niche social sites are up against the same issue. People are there to talk amongst or about themselves, and will likely send each other links than click on those preselected for them, in my opinion.

How much social traffic do You expect?

I have more than 100.000 visitors by search engines per month.

I doubt, that this is reachable by social traffic.

I've seen social networks working (locally) in favor of events, parties and gatherings of X interest. You have to be a trusted user (and active), but other than that, a regular web, I've seen no use actually worth the time invested.

Unless you are a very popular guy on a social network you will have to invest time to become popular or get attention. Other than that, the SN helps me to find potential partners. I mean, instead of me trying to gain attention, I look for the other ones in my niche making noise trying to get attention, recognize their work-time-investment and then I think of partnerships.

Or, if you organize events, get the attention of key members so they spread the word.

What's more valuable, 4 hours a week investing on a social network or on link building-writing content?

I've seen the same info. The couple of links I've added to social networks dont do anything for me. Think you would have to do this on large scale to get some little benfit.

The couple of links I've added to social networks dont do anything for me

In the German area, it's even much worse.

They had here 70 years ago the term "entartete Kunst" = "Degenerate art"

Now the new battle call in Germany is "He makes advertising"