Should you stop all your SEO endeavors and just spam social and links? Probably not a good idea. Ultimately there are many reasons to embrace social media in your marketing endeavors. Most of them have little to do with SEO. Embrace it because it makes sense to your business, not because it has magical ranking powers, and you’ll make out fine.
An interesting read here on SEW. Like the writer there, I’m not convinced there is any impact on search that social sharing has, despite some anecdotal evidence to the contrary. Instead my guess is that there’s a non-causal correlation between the two because the articles/links that are likely to be heavily shared on status networks come from people with broad circles of influence and with sites of their own that already rank highly for search.