Well, that's what it's supposed to do.
Recently, I noticed that Google Keep wasn't reflecting online what was on my phone, and when I did some digging, I uncovered the cause. This may apply to you for other reasons but if you are experiencing these symptoms:
Google Account (or most other accounts) is not synchronising web with device (e.g. Google Keep, Drive, Mail, etc.)
To fix this, you need to check that your Google Account (or most other accounts) is set to sync.
The path to follow is Settings ==> scroll down to Accounts and tap the account type you want to edit...
Select the Account to configure
In my case, initially, the account said "Sync is off" and it would only let me manually tap things to resync them. I couldn't set it to automatically sync.
Sync is OFF, dammit!!
To fix this, I had to go to...
Settings ==> Data Usage ==> (the three box column - what is that meant to represent anyway??) ==> Auto-sync data
|Auto-sync data must be checked|
|The four blobs middle right is another app, to be reviewed later :)|
And there you have it - sometimes the answers are simple but the path to enlightenment is not so obvious, to put a Sun Tzu / Jedi philosophical spin on it all :)
* I still miss my BlackBerry keyboard!