Why do you need to restrict access to some of your scripts or webpages? There are can be several reasons to do this:

• You can use some open-source php script (for example, statistics frontend), and you can not be fully assured that your data completely safe. Many open-source scripts have vulnerabilities, allowing hackers to gain access to your data, so you may want to hide this script "entry point" from others.
• You can have some important private data you don't want to be accessible by aliens.

So you need to "hide" your pages from search engine spiders, random visitors and other unwanted persons. In this article we'll examine several techniques how you can implement such "access restriction" with PHP..

This article explains how to restrict access to directories with HTTP Basic Authentication...

Just check out some large web 2.0 application directories at bottom, you may find that either small or portal sites are more willing to be web 2.0 style. It seems that web 2.0 is popular and successful at this moment and have become a trend on the web..