The button to suggest info for the encyclopedia is an email button.
For, most of you, using GMail and Google Chrome: Go to GMail, click the double diamond icon in the address bar and choose to "use GMail".
At the very least, if you have issues, you can right click on them and choose to copy the email address.
Below is a more comprehensive list of instructions for everyone.
Android (any browser) will ask for an appropriate email application to be opened with if one has not been set to "always".
Safari will attempt to use Apple's Mail.app .
Internet Explorer will attempt to use the computer's default email client - http://www.nextofwindows.com/how-to-handle-mailto-behavior-in-ie-chrome-opera-firefox-safari-on-windows-7/
Firefox will attempt to use your computer's default email client - http://support.mozilla.org/en-US/kb/change-program-used-open-email-links
Chrome will show a blank page if you've not set up a default email client - https://support.google.com/chrome/answer/1382847?hl=en