Let's say that yesterday I've had written an article that people liked and I've got about 30 links for that article. Now I'm curious if this move will increase the whole domain rankings, or just the rankings for that page ? Thanks
depends on the link pointing to it really. PR won't be increased at all if those 30 links are low quality!
Don't know which ranking you are talking about. Yes, if the right keywords are accommodated, it would help you boost the search rank a little bit. Don't panic much on page rank. Think of getting more and qualified visitors.
The links are high quality, because people liked that post and liked to him, with a short comment, like their oppinion about that post. And I was wondering if these links to that page will help the other pages from the domain to rank higher. Search engine rankings.