For monitoring the article mentions Pingdom. I have found New Relic's server monitoring [1] to be quite nice as well.

The nice thing is how it integrates with other New Relic monitoring for your app and that it actually is free.

[1] http://newrelic.com/server-monitoring

Great article. Super important everyone knows these services. Steve Blank also has a TON of great free resources on his blog: http://steveblank.com/tools-and-blogs-for-entrepreneurs/

I like how this post is broken down into specific categories. The most important tools are under "Analyzing and Improving". Obviously I use google analytics but haven't used Visual Website Optimizer. Is it like Optimizely?

Yes, it's very much like Optimizely. Here's a good (but old) comparison: http://www.quora.com/What-are-the-main-differences-benefits-...

When using the two tools I much preferred VWO editor that allowed to setup the tests. Besides that I found the tools to be quite equal.

things like crazyegg are good too. you can just use the 30 day trial to test it out.

Whilst technically true, “at the lowest level”, I find it hard not to take with a pinch of salt any article that describes Heroku as a “free service”.