Gabriel is correct, clearing the table will stop search from working.
If you do clear it the contents can be regenerated by running the updatesearchindex.php script. See: http://ez.no/products/ez_publish_cms/documentation/configuration/troubleshooting/i_need_to_reindex_my_site_for_search
As I dont use the search engine (using attribute filtering instead), I dont need this table. And it doesnt seem to be a problem anyway as I can regenerate it.
