Many bloggers are reporting similar jumps in Feedburner stats. Thirty percent or more seems quite common. My stats increased by 75 readers this weekend. Google Reader is apparently very popular.
I started 2 blogs last summer. One has Bad Behavior installed and one doesn't. Even though the one with Bad Behavior gets 10 times the traffic, Akismet has had to block less than half the amount of spam versus the blog without Bad Behavior. 2100 vs. 5000. Pretty darned impressive.