How to check backlinks to your blog/website?

As a blogger who concern about your blog's traffic, you need to check the backlinks to your blog.
Building backlinks is important because search engine like Google consider backlinks as one of the most important factors in their ranking algorithms. That's why you need to improve your link popularity and check out the backlinks.
The following services allow you to check the backlinks to your blog and website.
Google Blog Search: Search for «link:website address», example: link:www.kfblog.com
Technorati: Search for your website address, example: www.kfblog.com
Google Web Search: Search for «link:website address», example: link:www.kfblog.com
Yahoo Site Explorer: Search for your website address, example: http://www.kfblog.com
Windows Live Search: Search for «+link:website address», example: +link:www.kfblog.com

PageRank

PageRank relies on the uniquely democratic nature of the web by using its vast link structure as an indicator of an individual page's value. In essence, Google interprets a link from page A to page B as a vote, by page A, for page B. But, Google looks at more than the sheer volume of votes, or links a page receives; it also analyzes the page that casts the vote. Votes cast by pages that are themselves "important" weigh more heavily and help to make other pages "important". ”
In other words, a PageRank results from a "ballot" among all the other pages on the World Wide Web about how important a page is. A hyperlink to a page counts as a vote of support. The PageRank of a page is defined recursively and depends on the number and PageRank metric of all pages that link to it ("incoming links"). A page that is linked to by many pages with high PageRank receives a high rank itself. If there are no links to a web page there is no support for that page.

Obtaining backlinks from search engines

Most commercial search engines provide a mechanism to determine the number of backlinks they have recorded to a particular web page. For example, Google can be searched to find the number of pages on the Web pointing to Yahoo!’s Site Explorer is a method of obtaining the number of backlinks on a site.

Search engine optimization

Search engine optimization (SEO) is the process of improving the volume and quality of traffic to a web site from search engines via "natural" ("organic" or "algorithmic") search results for targeted keywords. Usually, the earlier a site is presented in the search results or the higher it "ranks", the more searchers will visit that site. SEO can also target different kinds of searches, including image search, local search, and industry-specific vertical search engines.
As a marketing strategy for increasing a site's relevance, SEO considers how search algorithms work and what people search for. SEO efforts may involve a site's coding, presentation, and structure, as well as fixing problems that could prevent search engine indexing programs from fully spidering a site. Another class of techniques, known as black hat SEO or spamdexing, use methods such as link farms and keyword stuffing that tend to harm search engine user experience. Search engines look for sites that employ these techniques and may remove them from their indices.
The initialism "SEO" can also refer to "search engine optimizers", terms adopted by an industry of consultants who carry out optimization projects on behalf of clients, and by employees who perform SEO services in-house. Search engine optimizers may offer SEO as a stand-alone service or as a part of a broader marketing campaign. Because effective SEO may require changes to the HTML source code of a site, SEO tactics may be incorporated into web site development and design. The term "search engine friendly" may be used to describe web site designs, menus, content management systems, URLs, and shopping carts that are easy to optimize.