I am using v1.1.1 of the WordPress.com stats plugin. Since I installed it (on the 30th of January), the statistics I see on wordpress.com have been odd, to say the least.
I realise that what I see on wordpress.com stats does not include my own page views, so those stats ought to be lower than the total views.
Here are the stats thus-far for February via wordpress.com: http://barrdear.com/john/stuff/wordpress_stats.jpg
Here are the stats for the same period from my host: http://barrdear.com/john/stuff/site_stats.jpg
For example, wordpress.com thinks that my "Beaten to the punch" post has seen 13 hits, but my host reports 3 views (1 entry, 1 exit).
What appears (to me) to be happening is that wordpress.com is recording hits to several posts against just one post.
As another example, my site gets aggregated here: http://ozpolitics.info/feeds. When someone clicks on the link on that page, they come through to the post-specific page on my site. WordPress.com stats are recognising ozpolitics.info/feeds as the referrer, but not the post-specific page as a hit. Here is a specific example: http://barrdear.com/john/stuff/stat_inconsistency.jpg
Notice that yesterday I got two referrals from ozpolitics.info/feeds. I only had two articles listed on the ozpolitics feed yesterday: "Idle Curiosity" and "Sweating the small stuff", neither of which is listed as getting a hit in yesterday's posts.