I would have sent an email to this blogger, but there's no contact information available on their blog (what's up with that?), so I'll respond to their post with my own.

Daily notes are useless. The value of a note is directly proportional to the number of times it is visited. That value is exponentiated each time a note is shared. Daily notes aren't revisited and they aren't shared.

First, daily notes are only useless if you don't have a system or workflow that makes use of them.

Second, they don't have to be shared to be useful. Depending on the system/workflow you have, they still have value. But the key is, you need to have system/workflow in the first place. Besides, unless the blog/website is setup like a daily journal, nobody is sharing their daily notes to the public. Typically what people would do is, write a bigger piece by expanding on ideas they wrote down in their daily notes.