you understanding programming, a process recursive means a function implemented and in it calls the same function, thus the process would be recuring always until comand or condition stopping it.
In Case google pagerank, google gives initial value pagerank for every page, at example of article Case carateristic google pagerank having 3 page, after given by initial value 1 hence to get value pagerank must be done iteration in the calculation.
From above example earned we to see that pagerank has been got after restating counted 3 times. But from publication google expressed that to get pagerank which either from overall of web page is done by restating process around one hundred 100 times. You can imagine what a the business server google in determining pagerank , by paying attention to structure link overall of web, number of outbound link, number of inbound link, the calculation out of billion web pages and repeats it 100 times.