At the end of 2012 I launched a search Engine that combined the offerings of six different second hand websites in Belgium. It was called 'Zoekertjesland' and indexed well over 3 million items.
Last week however I unplugged the server and stopped the project. I'm a student and renting a VPS for 2 years without any income from the website is costly.
In this post I'll walk you through the technical aspects of building a meta-search engine like this one (with PHP, MariaDB and Sphinx).