on the google webmaster guideline stated clearly http://www.google.com/support/webmasters/bin/answer.py?answer=35772&topic=8521&ctx=related Don't send automated queries to Google. and mentioned on top of page I just wonder some website privided the pr button service might use another server to query google.
hm, says all and nothing to me. i guess they talk about about software who scrape google results like this madeforadsense-sites, who display a large adsense block and the google results in same textstyle below for a keyword. but i think displaying a pagerank quite useless, because it dosnt says anything about the quality of the information (for a certain keyword) on a site. its like this "check engine" light in modern cars: you dont know whats wrong when its on, engine sounds ok to you, drives like always, maybe its just your service station who needs your money to turn this light off. one of the 21st century mysteries i reckon...
http://webicio.us/articles/computer...ation/measure-your-progress/google-page-rank- Google Page Rank Checker in PHP