URL Structure : Uniform Resource Locator, is a technical term for what is more commonly known as a website address.URL structure is one of the factors in determining how “search engine friendly” a website is. Search engines like clean, static URL’s. They don’t like messy dynamic url’s. URL structures should be static, and reveal what the page is about. A simple and clear URL structure is much easier for both search engine spiders and human beings. Static URL’s that contain keywords will often rank better than dynamic URL’s that don’t contain any keywords.Another problem with dynamic pages is load time. A dynamically generated URL comes from web pages that are generated from scripts, which put together page content from a database or multiple files on the fly by a server, when a user asks to see a website.
One is of a static url & the other is a dynamic url:
Static URL: http://seo-service-4-u.blogspot.com/2010/03/on-page-seo.html
Dynamic URL: http://seo-service-4-u.blogspot.com/2010/03/on-page-seo
1. Length of the URL: Try to keep your URLs short and descriptive no more than 3-5 words in your URL.According to Matt Cutts if there are more than 5 words…Google's algorithms typically will just weight those words less and just not give you as much credit.”
2. URL is case sensitive : Url is must be case sensitive of your site must be good for your site.
3. Keywords in URL: Try to use keywords in URL, if the particular page is about “What is SEO” then try to create a URL that looks like “ http://seo-service-4-u.blogspot.com/2010/03/what-is-seo.html ” as opposed to one that looks like “ http://seo-service-4-u.blogspot.com/2010/03/body-text.html ” See the difference?
4. Dashes are better than underscores : Google has no individual preferences (meaning you won’t be penalizes for either of the versions), dashes are more preferable as Google "SEES" each hyphened word as an individual one:So if you have a url like word1_word2, Google will only return that page if the user searches for word1_word2 (which almost never happens). If you have a url like word1-word2, that page can be returned for the searches word1, word2, and even “word1 word2?.
5.If you hesitate if your URLs may be perceived as spammy, check out SEOMOZ URL Spam Detection Tool that will estimate:
Spam words
Hyphens
Subdomain depth
Domain length
6. Mind your file extensions as they might prevent your pages from crawling.i.e. Don't end your URLs with .exe.