I recently purchased a Expired domain from auction and after I started my new site on it, I am noticing 500+ "not found" errors in Google Webmaster Tools, which are generating from the previous owner's contents.Should I use a redirection plugin to redirect those non-exist posts to any new post(s) of my site? or I should use a 301 redirect? or I should leave them just as it is without taking further action? Please advise.

Hi Paul would you please also have a look on my blog http://www.thetopblogger.com as I am also facing the same problem. When I search with the URL at Google, the URL appears on top but when I check with "Exact Post Title" from my bog, this doesn't pull the related post from my blog.

I checked more than 15 posts in this way and so far only 1 post ranked on #6 though the post title is exactly matching with my search.

I am not a expert at Robots.txt but you can check my blog's robots.txt file too. http://www.thetopblogger.com/robots.txt

Waiting for your reply Bro. Thank you.

Regards

Taswir