1script - 12:18 am on Dec 11, 2012 (gmt 0)
But a site as a whole does have a crawl budget, at least that's my understanding of the current conventional wisdom. I do remember there was talk about it and also about "using it wisely" as in not creating too many bad URLs that Gbot crawls only to realize that that those are not the URLs to index.
Remember that every URL has its own PageRank score, so PR is not something that a "site" has.
How the crawl budget is assigned to a site is a bit of a mystery to me but I do make an assumption that this is a measure of the site's standing with Google overall. Call it homepage PR or something else but there must have been reason they put "Crawl Stats" into the "Health" section of WMT.
Complex alphabet sorting algorithm ;) LOL.
Then they put those URLs in a crawl list which is prioritized by a complex algorithm.
BTW, how would individual ranks of pages explain alphabetized carpet-crawing? It would seem that the alphabet order of URLs would have no correlation to the distribution of rank (in any way, shape of form that it's doled out) between the pages. So do they have different prioritized and "OMG-we-dont-know-what-to-do-with-these-urls-but-want-to-index-them-anyway" crawling lists?