mod rewrite why?

[mikemcs]

What are the advantages of using mod rewrite as apposed to using a query in your URL to determine what page to show?

[jeremy goodrich]

Some search engines limit the urls that they crawl to those with 1 or at most 2 variables in the string.

So, products/widgets/10 might be OK for a search engine, while

products.php?item=widgets&price=10

might not be fetched by any crawlers because it has 2 variables. Though I am seeing more dynamic stuff indexed than in years past, it's still a consideration to keep in mind. :)

[Fischerlaender]

There is another reason for using mod_rewrite:
A URL which looks like
/article.php?cat=123&id=456
isn't very nice for human visitors, whereas
/article_123_456.htm
is easier to understand.

And of course you can even go one step further and use an URL like:
/marketing/456.htm
(assumed that the category #123 contains pages on marketing)

In other words: With mod_rewrite it's easier to use URLs which tell the user what they will find behind it.