Good knowledge about:
+ Web Scraping & Data Mining,
+ Big Data Processing,
+ SEO (Search Engine Optimization),
+ Internet Marketing/Advertising,
+ E-commerce,
+ Amazon Services,
+ Google App Engine,
+ Linux OS,
+ Queuing System.
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Some techniques:
+ Python,
+ Zero Message Queue (ZMQ),
+ PHP-Yii-Zend-Smarty,
+ Javascript-Jquery-AJAX,
+ CSS Styling,
+ HTML/HTML5,
+ MySQL, PostgreSQL,
+ MongoDb, Cassandra, HBase,
+ Apache Solr,
+ Hadoop, Map-Reduce.