How often do search engines crawl the web? A report by Dirk Lewandowski, Henry Wahlig and Gunnar Meyer-Bautor of the Department of Information Science at the Heinrich-Heine-University Düsseldorf, Germany looked at websites with daily updates and concluded that many were not crawled more than once every 20 days. There are specific issues identified at Yahoo, and to a lesser degree MSN which often seem to have out of date caches.

The study was undertaken using the expression “Helicopter crash in Iraq”, and looking at updates from Reuters.

The implication of this for communications business professional is that even with daily updated content you cannot be sure that your content will be found by any search engine.

Unless you are using RSS and blogging techniques to ensure that your content is published to as many intermediary sites as possible your story may not even be indexed by major search engines within the news cycle. The implication of this study is that even if a PR professional puts up a press release on their own site and on e.g. PR Web, it might not be being indexed by the major search engines, and is therefore unlikely to be found the 75% of users who use search engines to find information about companies.