Sorry if this is a repeat question, but do crawlers from myriad SE's visit at (ir-)regular time intervals? I was thinking about inserting a cgi date/time script (stamp) or similar, waiting for G or Y! to cache (not that SE crawling and caching are concurrent activities TTBOMK) , keeping track of cache freq (via stamp), and (ergo) predicting some type of timing pattern. Anyone tried this?