Every good website should have an option to search the content of the site. Although MCMS does not ship it's own search engine you can easily integrated 3rd party search engines with MCMS. If you go and simply add the MCMS website as content source to a search engine you will experience a couple of problems:

• searching for strings which are part of navigation controls or of the template will cause all the affected postings to be returned - which is usually not what you want to see.
• javascript or XML navigation links cannot be followed by the crawler which might mean that only the first page of the site will be crawled
• incremental indexing does not work out

To avoid these problems you need to add additional logic to your site.

Here is an article explaining how to exclude the navigation controls from the crawl
(This article also has a solution for the javascript or XML navigation problem at the end)

Here is an article explaining how to enable incremental indexing