Evernote

https://evernote.com/
Great application for just about anyone. application appears to be free, and provides a free level of basic service. It appears to be very popular with millions of users on multiple platforms.

However, the latest updates require administrator level authority. A portable version would seem very desirable.

I submitted the suggestion, and their "helpdesk" replied that USB sticks varied too much to make it possible. Huh?

Just an idea.