Compete.com stats are often wrong. They say HN's traffic is down from last fall, and in fact it's sharply up.
Only good for larger sites, as it doesn't cover smaller ones
Here is TC http://trends.google.com/websites?q=techcrunch.com&geo=a...
Here is HN http://trends.google.com/websites?q=news.ycombinator.com&...
PG - how accurate is it? Suggests ~20k daily uniques to ~50k now
http://www.ycombinator.com/images/hntraffic-2apr11.png
Pageviews are thrown off somewhat by crawlers, but unique ips shouldn't be.