Magento's stock search is pretty basic, and although it offers a "sort by relevance" feature I often can't tell what it was thinking from the order of the result set. So I decided to hit the database directly and dump out the weighted scores to view them numerically. Now, this doesn't "dix" anything - but at least it gives me the ability to adjust the indexing algorithm and see the results of my efforts.
The following code will do just that:
SELECT prodName.`value` AS name,
MATCH (searchIndex.`data_index`) AGAINST (' ') AS relevance
FROM catalogsearch_fulltext AS searchIndex
LEFT JOIN catalog_product_entity_varchar AS prodName
ON prodName.`entity_id` = searchIndex.`product_id` AND prodName.`attribute_id` = (SELECT attribute_id FROM eav_attribute WHERE attribute_code = 'name' AND entity_type_id = 4)
ORDER BY relevance DESC;
Give that a shot, and see how Magento is adding weighting scores to your search result sets. Then go ahead and upgrade to Solr Search so you can get a REAL index & search solution!