If you don't know about the email processor, briefly it's a way to file emails into CiviCRM as activities, and less briefly, see http://book.civicrm.org/user/current/advanced-configuration/email-system-configuration (about half way down).
I've been doing some fiddling with drag and drop and, in particular for CiviCase, it would simplify the process of getting the emails into CiviCRM. It also removes the need, if you're using the IMAP method, for storing everyone's individual email passwords in the CiviCRM admin page settings. And it would work with attachments.
One possibly big drawback is it would only work in native email programs, like Outlook, Thunderbird, etc. It will NOT work when viewing your email via webmail/browser, but I think there's a big enough pool of people and organizations who use native email programs that this could be worth it.
Currently for CiviCase it's a multistep process, where you have to first use the email processor, then wait until cron does its thing, then go find the email in CiviCRM, then choose File On Case. My goal is you could just drag the email from the inbox into an open CiviCRM browser window, fill out some info in a popup box, and then you're done. Ideally, if you already had a Manage Case screen open, it would default to that case.
I don't have anything actually coded yet, so I'm mostly posting this to gauge interest and to see if anyone has maybe already done something like this or is interested in helping.
This sounds interesting. My only concern is it seems to require human-intervention on an ongoing basis. I would love to see something that is more automated, at least after any initial setups are completed. Another product that I use does somethings similar to this extremely well, unfortunatly is not open source. I use Basecamp for tracking projects and one thing it does a great job of is automatically filling any inbound emails to the correct project. So if I open any of my projects, I see ALL history listed including any emails. (Some of the people involved in a project use their personal email exclusively, and never login to the basecamp website. Yet when I login to any of my projects, it has the complete history with all emails)
We use a closed but relatively cheap tool called CRM linker. It's an Outlook plugin. I like the fact that it pops up when you hit send reminding them to log emails, it has transformed the amount of contacts with supporters we are logging. Drawbacks are that it is closed, outlook only and doesn't log inbound emails. In reality all it is is a method to remind users and add the inbound email processor as a bcc. It has the capability to log emails to a specific case but that requires a unique email address, something which other CRM offers but Civi doesn't.
A Civi implementer in London started a Civi specific plugin which they mostly finished, but they have so far ignored repeated requests to share it. I did some research and I think they based it on an open source vTiger plugin.
None of the above are drag and drop though, that would be nifty. However I am a big fan of a pop up on send, it's a big reminder to users.
This sounds appealing - although I don't have specific users in mind.
On the in-client mail integrations - if you are not already aware of it Xavier has written an LDAP integrations which allows you to add CiviCRM contacts as it if were another address book in your email client (much as users in an MS exchange environment experience the contacts stored on the company Exchange server)
I've abandoned work on this, mostly because on a mac it requires two awkward extra steps every time you file, but if anyone's interested there's a snapshot here: https://github.com/demeritcowboy/com.physicianhealth.emaildragdrop