A long tail keyword is a highly targeted search phrase of three or more words. Usually a long tail keyword phrase will include a head term which is a more generic keyword (e.g. picnic) and one or more other words that refine the search to make it more specific (e.g. blanket waterproof). Long tail keywords are therefore more qualified and have a higher chance of converting if they land on your website.
Conversion marketing – Glossary of Conversion Marketing.
Over 300 tools reviewed – Digital Marketing Toolbox.
A/B testing software – Which A/B testing tools should you choose?
Keyword research – How to do keyword research.