Default: “Ugly”
The default looks like
http://example.com/?p=N
where N is the Post ID number. It works on all server environments, but it doesn’t look as nice as some of the other options.
mod_rewrite: “Pretty Permalinks”
Using mod_rewrite or lighttpd you can produce much nicer permalinks (see Pretty Permalinks). There are many different formats, but the most common, and most versatile looks like
http://example.com/2012/post-name/
or
http://example.com/2012/12/30/post-name
