I have a website about Delhi and its tourism spots. Now for giving information about these spots, I am using Wikipedia and any other website for the information content, but I want to give Credit to these sites and don't want Google to spam my site for duplicate content. Can anyone suggest some legitimate way to tell Google that I am giving the due credit to the original source pages but I also want to rank for these pages. (I will not be posting the exact content from these pages, but only used for reference). Since my site is NOT a news site, is it okay to use the original-source metatag? Or there is some other way around? Please help!
Make sure you are using the content in accordance with the license that you have to copy, modify, and share it. In the case of Wikipedia (described here) that is the Creative Commons Attribution-Sharealike 3.0 Unported License (CC-BY-SA) and the GNU Free Documentation License (GFDL) (unversioned, with no invariant sections, front-cover texts, or back-cover texts). For Wikipedia under the CC-BY-SA license you must attribute the content to them with a link and you must license any derivatives under the same license.
The link to Wikipedia is also good for Google SEO. Google is much less likely to penalize your site for duplicate content when you use a specific deep link to the original source of the content.
The other way to prevent Google from penalizing your site it to prevent Googlebot from indexing that content. You can either put those pages into robots.txt so that Googlebot can't even crawl it, or use the meta robots noindex tag on those pages.
If you're only quoting small chunks of information, just code it appropriately (
<blockquote>) and provide a link to the original.
If you're copying whole or substantial chunks of Wikipedia and other sites' articles, with or without attribution, it's duplicate content and will be treated accordingly. You may run into copyright issues with the "any other websites" too, depending on who they are.
Google, and indeed most search engines, don't want sites to duplicate entire pages of content. So unless you're adding value – and if you're taking whole articles, that's going to have to be a lot of value – you will be penalised for it.
Google's Matt Cutts talks on the issue here.