Any organization that spends money for marketing research or generating sales leads can benefit from building a web crawler. Instead of spending tens of thousands of dollars for a boxed market research survey, a web crawler can be used to ferret information from the web.
For example: 1. Retail oriented companies can build web crawlers to find trends mentioned in web logs. 2. Software consulting companies could crawl industry specific news groups and mailing lists for potential customers asking for advice. 3. Job placement services could search company sites for an increase in Job postings.
All of these tasks can be accomplished with creative use of Perl and it's abundance of CPAN (Comprehensive Perl Archive - the repository of Perl module/libraries) modules. In this article the main topic will include some of the CPAN modules available and how they can be used to accomplish tasks similar to the ones above.
Why Perl? Why not? Perl is an excellent tool for a web mining project. Perl's basic but powerful built-in data structures, easily accessible regular expressions and large selection of CPAN modules show that Perl easily meets the application's requirements.
The rest of this article will discuss some CPAN Modules that will be useful when building a Perl-based web crawler.