Here is a conversation with a googlebot which may give some indication.
It comes from Seochat a truely great site.
A conversation with Google
A conversation with Google's automated crawling software (or "spider"), otherwise known as the Googlebot, might sound something like this.
You: Excuse me, Googlebot, why doesn't mysite.com rank well in Google for the keyword "help me?"
Googlebot: (raises a harried eyebrow and looks annoyed) Where shall I begin?
First of all, your code is a mess. You have more lines of code than actual text and so many nested tables it makes my head spin.
Your home page has a keyword density of 24 percent, which is suspiciously high compared with the top-ranking sites in my database, all of which average about seven percent. Are you keyword stuffing? You know I don't like doorway pages!
You only have 12 backlinks going to your home page that I recognize, and six of them are from within your domain.
The top ten sites have an average of 300 backlinks in my database and literally thousands of backlinks in Yahoo and MSN (not that I care about those hacks).
I've slapped you with a duplicate content penalty because I noticed that www.anysite.com has the same exact home page copy as you. Don't look so surprised - I don't care whose fault it is!
On average, your site is 60 percent slower to download than every other site in my database and all your dynamic URLs are giving me a headache. Honestly, do you really need so many variables?
Make free money from your website
Why doesn't Google like you?Your Code is a Mess
Your keyword density is high compared with your competitors
You're keyword stuffing
Your home page looks like a doorway page
You have fewer backlinks than your competitors
You have poor link partners
You're linking to a site that's banned
Your backlink text is repetitive
You have no fresh content
You have duplicate content
Your site is slower to download compared to your competitors
You have dynamic URLs
You don't have a site map
Your navigation is image-based
You have no ALT tags or meaningless ALT tags
You don't have a site map so I can't easily crawl through the pages of your site, and all of your navigation is represented in images without meaningful ALT tags, so I don't know where I am when I click away from the home page.
Your link partners are abysmal - they are not contextually relevant (which makes me suspicious) and you repeat the same exact words in the linking text, which makes me think you're doing automated link swapping.
I've been here three times in the past month and your content has not been refreshed once.
I can't be bothered with you and your stale, over-optimized content.
I will be back to crawl you again sometime this century.
Sincerely Yours, The Googlebot.
Don't get hung up on the PageRank
For many people getting a higher PageRank (as seen on the Google bar) is a mark of success. However the Google representative notes that:
"We have a bank of machines that computes PageRank continuously, but we only export new visible PageRanks every 3-4 months or so."
So take little notice of changes in your PageRank, or in trying to reach a certain PageRank level. Just focus on making good pages.