Reader Question: I just came across your article in WebProNews on keyword registration and found it very helpful. The article also stated that you might answer other SEO questions, so here goes: We are a stock illustration agency and our site is programmed in a Mac environment and served on a WebStar server. Because of our heavy lasso coding, we must use the tag “.lasso” on most of our pages. Does this negatively affect our search engine rankings, and so, is there way to work more effectively with the situation? Any input would be most appreciated.

Answer: This is a great question because it deals with and aspect of search engine marketing (SEM) that few companies address well: URL structure and file extensions. Plus, it’s nice to know that I’m not the only designer who creates Web sites primarily on a Mac. There are many misconceptions about search engine optimization and URL structure.

File extensions

The extension of files (.lasso, .cfm, .asp, .php, .htm, .html, etc.) does not make any difference on the ranking whatsoever, according to a software engineer at Google. Though I have to admit that some of my colleagues disagreed with him at a recent Search Engine Strategies conference.

My colleagues felt that Web page with a file extension of .htm or .html is more likely to be crawled than a Web page with a different file extension. My personal experience? In the past, this observation appeared to be true. Even I noticed that pages with a Cold Fusion extension (.cfm) appeared to be crawled more easily than pages with an Active Server Page (.asp) extension. But search engines have evolved considerably over the years. I now side with the software engineer at Google. I don’t believe the file extension makes a difference on whether a page ranks or not.

Web server performance

What does make a difference is how quickly a server delivers a Web page to a search engine spider. So if your server environment is overloaded (with too much traffic on one site, or an accumulation of traffic from a lot of Web sites), it might deliver pages more slowly.

Additionally, all servers need regular maintenance. Sometimes, a search engine spider might request a page from your server during maintenance times. Google, in particular, will not request pages from your server and automatically determine that the pages no longer exist. The spider will revisit your server two or three times before making that determination.

Dynamic vs. static URLs

Many people mistakenly believe that a dynamic URL is one that contains a question mark (?) in it. A dynamic URL is one that is generated on the fly. Dynamic URLs can have no question marks in them. So they appear to be static. Likewise, static URLs can have question marks in them.

One common misconception is that search engines will not crawl a URL with a question mark in it, such as the URL shown below:

www.yoursite.com/page.asp?ID=172

Basically, if you copy and paste this URL into a browser, deleting everything past the question mark, like this:

www.yoursite.com/page.asp

If the page loads, then search engine spiders should not have any problems crawling this type of URL.

Search engines have become increasingly better at crawling more complex URLs. If you have a database-driven site that generates URLs with a lot of parameters, it might not “It [a URL] could have one, two, three or more parameters,” Matt Cutts, a software engineer at Google, stated at a recent Search Engine Strategies conference. ” The more there are, the more hesitant Google will be to crawl those pages.”

For example, this URL:

www.yoursite.com/page.asp?ID=172

is more search-engine friendly than the following URL:

www.yoursite.com/page.asp?CatLevel=2&Cat1_ID=27

Think of the question mark as a “red flag” that communicates potential problems with spidering. A question mark can indicate delivery of: