Knowing how many people are on your pages at any one time isn't a meaningless number. You're right in the sense that it's not a great way to assess quantitative site load. I just used that number in the blog to give a qualitative assessment of how many people were currently on my site.
Also, you are misunderstanding this chartbeat number. These 282 visitors weren't spread out over 45 minutes. These are real time users. Granted, some users are idle but most are interacting with the pages.
If this blog post were about the specifics of server load from a #1 HN post, I wouldn't even use the chartbeat figure. The post was about middleman + s3 + cloudfront. The chartbeat figure was more than enough to give readers a qualitative glance of how many people were looking at my site.
Also, you are misunderstanding this chartbeat number. These 282 visitors weren't spread out over 45 minutes. These are real time users. Granted, some users are idle but most are interacting with the pages.
If this blog post were about the specifics of server load from a #1 HN post, I wouldn't even use the chartbeat figure. The post was about middleman + s3 + cloudfront. The chartbeat figure was more than enough to give readers a qualitative glance of how many people were looking at my site.