I wrote about a mobile phone and today i got 2 comments on it. When i searched in google then i found the comments were picked from a review which was posted on another website should i approve them. is it effect my ranking as the lines were from another website
you should not allow those comments, because i think they'll be considered as spam by search engines..
It probably won't hurt, especially if it's just a sentence or two from another site. But if you think about it, whoever is leaving these copy & paste comments is probably a spammer just trying to get their link on your site. You might not want to encourage that behavior by approving these comments.