Without doing this, not many pages on your jobberbase will have a completed description and keyword metatags. Some search engines still use these tags to determine what the page is about.

This mod adds some of your keywords plus dynamic description and keywords taken from job title, company name...

In your jobberbase root folder open page_job.php and on the very bottom, one line above "?>" add

//description and keywords mod
$meta_description = stripslashes($info['title']) . ' ' . $translations['jobs']['preposition_at'] . ' ' . stripslashes($info['company']) . ', this is a description of your ad, it is very cool, if you have a job webpage in Canada we can trade links...';
    $meta_keywords = stripslashes($info['title']) . ', ' . stripslashes($info['company']) . ', mykeyword, mykeyword1, mykeyword2, mykeyword3, mykeyword4, job listings, jobs, post jobs free';

Make sure you replace the example description and example keywords with your own!

There are several more pages that are missing keywords and you can add them in a similar way.

In page_company.php (root folder) there are missing keywords, what you could add is:

//descriptions and keywords mod
$meta_keywords = 'keyword1, key word2, keyword3, keyword4, keyword5, '  . $company;

right before:
$template = 'company.tpl';

Again replace keywords with your keywords!

Other files that just need your unique description and keywords are:

page_rss.php
page_write.php
page_home.php
page_companies.php

Since for these pages description and keywords can be static you only need to add, usually close to the bottom of the page:

$meta_description = 'Your description goes here';
$meta_keywords = 'Your keywords go here';

This should cover 95% or more of all your relevant jobberbase pages with unique descriptions and keywords.