A 10X increase in GreenM3 traffic increases latency, what was hitting my site?

Last night I wrote about Amazon.com’s Cloud Drive, and noticed a 10X increase in traffic.

Which was actually unrelated to the post as a dump of the traffic shows a bunch of repeated URLs hitting only the home page.

Latency spiked, but the site stayed up.  The following is from Pingdom monitoring www.greenm3.com.

Curious I am going to contact SquareSpace support to see if they were showing any other activity like this to their site.

The quick response from SquareSpace gave me the answer in 3 minutes.  Very cool.

This is a form of spam. Robots attempt to add comments on pages with forms in hopes that your website posts comments without moderation. They're not actually trying to hack into your account -- they're seeing the form and trying to leave a reciprocal link for the site they're promoting.
We've been trying to block these, but occasionally they slip through. No need to block the IP -- the fact that they hit the site so many times will alert our spam filters.
Sorry for the troubles.