There are many open-source e-commerce scripts a web designer can employ. Here are some of them with my personal opinion.

1. Virtuemart - This is an excellent e-commerce component for Joomla. I have used it in several of my websites.

2. Ubercart - This is an excellent e-commerce module for Drupal.

3. Wordpress e-commerce plugin - This plugin provides simple e-commerce capability in Wordpress.

4. Zencart - This is a derivative of OSCommerce. Again, I didn’t like anything that is related to OSCommerce.

5. Magento - This is the latest and very promising e-commerce software.

6. OSCommerce - OSCommerce is the oldest e-commerce script. It is now out-dated and the code is difficult to maintain.

Other less popular e-commerce scripts are OXID esales, Freeway, simplecarts, Digitstores, opencart, Prestashop, dashcommerce.

For better integration with other CMS, I will continue to use Virtuemart, Ubercart and Wordpress ecommerce plugin. I may also use Magento in the future.

One of my clients has asked me to embed web traffic stats on his website. Generally, I monitor the web traffic using Google analytics or stats script provided by the web hosting. However, these do not allow me to embed the stats on the website. After googling, I found this amazing open source web analytic software, PIWIK, that allow one to embed stats data and charts on the website. The software is a mimic of Google analytic but it is free and open source. PiWik is almost comprehensive as Google analytics. Some of the key features of PiWik are: