Question

I am making share a link feature like facebook. Currently I am parsing meta tags to get keywords, descriptions e.t.c but how to parse these type of pages http://en.wikipedia.org/wiki/Wikipedia There is no meta description for this page but facebook still fetches the following description:
Wikipedia ( /ˌwɪkɪˈpiːdi.ə/ or /ˌwɪkiˈpiːdi.ə/ WIK-i-PEE-dee-ə) is a free,[3]web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 17 million articles (over 3.4 million in English) have been written collaboratively by volunteers around the

How can I extract such description if there is no meta description tag found on the page.

Answer 1

Looks like they generate the description the same way Bing does which might be difficult to easily re-create:

How does Bing generate a description
of my Web site?

The way you design your Web page
content has the greatest impact on
your Web page description. As MSNBot
crawls your Web site, it analyzes the
content on indexed Web pages and
generates keywords to associate with
each Web page. MSNBot extracts Web
page content that is most relevant to
the keywords, and constructs the Web
site description that appears in
search results. The Web page content
is typically sentence segments that
contain keywords or information in the
description tag. The Web page
title and URL are also extracted and
appear in the search results.

If you change the contents of a Web
page, your Web page description might
change the next time the Bing index is
updated. To influence your Web site
description, make sure that your Web
pages effectively deliver the
information you want in the search
results. Webmaster Center recommends
the following strategies when you
design your content:

* Place descriptive content near the top of each Web page.
* Make sure that each Web page has a clear topic and purpose.
* Create unique <title> tag content for each page.
* Add a Web site description <meta> tag to describe the purpose of

each page on your site. For example:

> <META NAME="Description"
> CONTENT="Sample text - describe your

http://www.bing.com/toolbox/support/faqs.aspx

One option would be to hit Bing and try to fetch the description from there.