I'm a very casual Evernote user; I only use the free version, every few months, to sync basic things (e.g., shopping lists, or directions) between my desktop and phone.

A few months ago, I noticed that there were suddenly lots of ads within Evernote, encouraging me to upgrade to the paid version. I'm not complaining, since they need to make money, but it did strike me as being more aggressive than before. Now I understand what was (is) happening.