I set up a filter on my Gmail that automatically tags emails from myself with "Notes". Extremely easy to add a note anywhere -- just email myself from my phone.

I set up a filter on my Gmail that automatically tags emails from myself with "Notes". Extremely easy to add a note anywhere -- just email myself from my phone. Easy to search -- just add "in:Notes" to the criteria. Only thing it doesn't really cover is linking between notes. Though I wonder exactly how valuable that is anyway, when you have a powerful search available.