Joomla! is a content management system that places a small line in the source code of each page:

<meta name="generator" content="Joomla! 1.5 - Open Source Content Management" />

Now, this line simply promotes Joomla! 1.5 if a visitor of your site looks at the source code to see what system you are using, as they may be keen to use the same system.

However, this same line is also visible to people who are looking for sites to hack.

It also adds an extra line to your page and this line is not really needed, so you should remove it. The patch will remove this line for you.

For your Search Engine Optimization efforts you want the cleanest code possible, so I remove the extra line of code from my sites.

The Copyright field adds another meta tag line to your source code that contains the copy right information you add in that field.

If you have a web site where several people write articles, you could use this field to show the copyright for that user, for that year.

For example, if the article is written by Herbert-Jan van Dinther, you can fill this field with "Herbert-Jan van Dinther—2009".

If you are the only editor, you don't need this field, so remove it—again cleaning up the source code.