The truth is simple - when I see an article with lots of shares in the social site counter (facebook, twitter, Google+, etc.) next to the article it is clear that this article became viral and probably has very much value in it. Today I was reading the article called 6 SEO Tips from Google Itself and my eye catched on sentence: I know the fact that +1s can affect search engine ranking in Google. But how is with other social sites? Does likes, tweets and etc, can be indicators for search engines, that one or other article has lots of value in it? Want to hear your thoughts here...
Social Media site use to increase traffic of your site mean refer visitors other then search engine. So i think this does not cause any effect on ranking.
+1s only affect personalised search. So if you (or one of the people in your circles) has +1 a page, it will influence your own search results. So, the use of it is minimal in terms of improving SERPS. However, overall, social media is definitely positive for SEO. Having a presence on different social media provides different ways for people to follow you and for you to transmit your message. It's completely white hat (as long as you're not faking followers, +1s, likes, etc), so you won't get penalised for it. All these social media sites can provide positive signals to SEs.
But as Google started to pay high attention to the value of content, it can be one of the indicators, that this content on the site is not just a crappy sh*t. If people are sharing something, this means it's worthwhile to read, so this means this article should get higher search engine positions, isn't it? I already saw on my own, that the first thing, which I check, when I open an article, is the number of shares in social buttons next to it. And if I see high numbers in it, this is an indicator that I should find something really cool here. Sometimes it is even inspire me to share it as well. Probably it is herd mentality - if everyone is doing, I should also do it. So, it is just interesting to me, how does it works with search engines?
That's the theory, but if someone is using a bot (or even manually) to get the likes, +1s, tweets, etc, then it's not a reliable indicator. From an SE perspective, it's all signals to show activity in the social sector. Google doesn't consider likes, but Bing does. Facebook links are nofollow, so don't carry the same weight. They are often on private pages anyway. As I mentioned, Google+ shares/+1s only influence personalised search. I did a test for this: a site I +1 a post for comes up as #9 in SERPS for a fairly competitive term. However, if I disable personalised search, it doesn't even feature in the top 50. However, Google+ links aren't nofollow, so if they are public then they can have some weight, just like any link. The other search engines aren't relevant (and Yahoo uses Bing).
I don't know how much this stuff is really in the algo yet. But I think it's smart to be doing it. There is real traffic to be generated... And my gut tells me that it is in the algo at least a little bit already (but not huge yet). Maybe if Plus really takes off things will change (again).