Today for the first time, I noticed that Google Webmaster Tools has offered me the Fast option under the Set Crawl Rate section. I was able to set the crawl rate for this particular blog to Fast, and it will remain set to Fast until Feb 28, 2008 - at which time it will apparently revert back to normal. I would expect at that point that if the Fast Crawl Rate has served a purpose, then Google will allow me to set my Crawl Rate to Fast again.
The blog that received this Fast Crawl Rate is a blog that I have been steadily posting on and have been getting a fair amount of Google Search Traffic (20-30 visits per day). I don’t know exactly what factors play into the Fast Crawl Rate ranking, but it seems to more than simply having steady postings. I usually post once per day, Monday - Friday. I have had other blogs that see this level of posting, but had yet to receive the Fast Crawl Rate.