I tried using the Gmail webapp and unity mail, but neither of them light up the notification indicator (the envelope does not turn blue). Unity mail doesn't even show up in the messaging menu. What can be done to fix them, what are some alternatives?
Ubuntu – Which Gmail notification app will work with 14.04
emailnotificationunity
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As far as I know, each account you set up with Evolution will have its own inbox showing because they do not share the same inbox. I use Evolution with my school email and Gmail addresses, and they have 2 different inboxes in Evolution.
I'm not sure myself; I am actually wondering whether this could be filed as a bug report on Launchpad.
They do on my system, at least when Evolution is open but its window does not have focus.
Lots of mail-notifiers (Popper, GmailWatcher, Gmail-Notify) stopped working from 12.10 because of change in messaging-menu api. You can always file a bug on their respective launchpad page.
However there are few which works with new api ( Unity-Mail, Thunderbird, Evolution).
Unity Mail 
Launchpad: https://launchpad.net/unity-mail
With Unity Mail we can handle multiple gmail accounts. You will get an OSD notification whenever you receive a new mail showing the sender, and the subject of a mail.
In addition it adds a launcher icon to display the count of unread messages, integrates with the mail indicator to turn it blue, and displays a list of mails in the drop down menu there.
PPA: ppa:mitya57/ppa
Source: askubuntu
Best Answer
Mail Notification app works for me.
I have tried unity-mail also, but no notifies at all. Tried with different accounts.