Does the site provide rss-feeds? That might often give you more resonable data. How often do your script check these sites? If it checks reasonably often, you could maybe use your own time when the site lack something better?
no, unfortunatly not all sites offer rss yet, and even then, a lot don't contain dates. I don't want to run this all the time. Basically, I'd like to do a search on a particular topic on the site, get the results back, take those links and turn them into a date ordered list.