Apple's Mail.app has always worked fairly well for me. But, it lacks some of the customization and "power user" features that you can find in specialized mail applications or even using some Gmail's popular "labs" extensions. However, Apple Mail can be customized and enhanced. To that end, I thought I'd share a couple of add-ons I use in conjunction with Apple Mail to help manage my email more effectively.
Spam Sieve - $30
If I could only pick one add-on to use with Apple Mail, this would likely be it. Mail.app's junk filter has never worked well for me. SpamSieve is client-side (meaning it works on your Mac, not on the server). It uses a technique called Bayesian spam filtering that is constantly adapting to determine the probability a message is spam based on the words in the message.
The first time you install SpamSieve, you train it by allowing it to sift through messages you've already classified as good or spam so it knows the types of messages you receive. It will also allow you to maintain a whitelist/blacklist of contacts you never want to be marked as spam or always want to be blocked. Gmail does a pretty good job of filtering my messages, but for messages that come through on other accounts, SpamSieve has been a lifesaver.
Bonus tip: If you can, run SpamSieve on a Mac that's always on and if you use IMAP for your email, the spam filtering will also filter messages on your other machines and iOS apps.
ForgetMeNot - $9.95
Too many times I've suffered that embarrassment of meaning to send someone a file attachment but forgetting to actually attach the file. ForgetMeNot solves this problem. It scans your email for keywords that indicate you're likely sending an attachment. If no file is attached and you've hit send, a warning dialogue pops up reminding you and giving you an opportunity to attach a file.
ForgetMeNot comes with a series of pre-defined keywords in a variety of different languages, but you can add your own if you tend to use custom words or phrases when attaching files. For number of times, ForgetMeNot has saved me embarrassment. It's well worth the price.
SendLater - $9.95
I check email regularly for the day job, including at home in the evenings and on the weekends. I try to respond to messages quickly, if nothing more than to process and get them out of my inbox. However, I want to be careful about setting the expectation with clients that they're going to receive an immediate reply from me or that (barring an emergency) they will receive a reply outside normal working hours. SendLater allows me to compose the response to an email now, but send it automatically at a later day or time.
Once installed, a second send button with a clock is added next to the regular send button in Mail.app and you can choose to respond at a specific date and time, a certain time from now (i.e. 20 minutes from now) or on the next business day. SendLater is made by the same developer of ForgetMeNot. You will receive a slight discount if you buy multiple add-ons at the same time.
CargoLifter - $9.95
I'd like to remind everyone that email was never meant as a mechanism to transfer large files. A common reason for bounced or undeliverable emails are because they contain large file attachments. For years, I've used Dropbox to solve this problem by sending a link to the attachment in the body of an email to a file. CargoLifter makes that process easier by automatically uploading large email attachment to the cloud, and adding the corresponding links at the end of your message.
CargoLifter works with a number of services including Dropbox, Google Drive, CloudApp, Box and Hightail (formerly YouSendIt). You can optionally configure the file size threshold at which CargoLifter kicks in (I set mine at 5MB) as well as customize the instructions for downloading your attachment. This helps keep both the sender and receiver's email inbox free of bulky attachments and increases the likelihood of your message being received. CargoLifter is made by the same developer as SendLater and ForgetMeNot so, again, you'll receive a slight discount if you bundle your purchases.
Bonus tip: I use Hazel to monitor the CargoLifter folder created in Dropbox and automatically clear out files older than 7 days to free up space in my Dropbox and help keep my attachments more secure. I've customized my message in CargoLifter to tell recipients the link expires in 5 days to encourage them to download their message timely.
Attachment Tamer - $14.99
One of the most irritating experiences with Mail.app is the way it handles attachments. Sometimes it shows photos or PDFs inline (i.e. shows previews of the documents) sometimes it shows them as icons. I'm sure there's a reason behind this, but I can't figure it out. Attachment Tamer allows you to adjust how Mail.app handles attachments. You can choose to display only certain types of attachments inline and choose where in an email your attachments should go. Attachment Tamer also formats your attachments and offers better compatibility with Outlook, Exchange and PC based email systems when handling attachments.
You can also adjust inline attachment viewing by a terminal command:
defaults write com.apple.mail DisableInlineAttachmentViewing -bool yes
If you decide later you want to return to normal behavior, change the "yes" to "false" (without quotes) at the end of the string. However, changing this setting via the terminal changes it for all attachments (including graphics typically included with email signatures, etc) and can result in some unwanted and unexpected behavior. That's why I prefer Attachment Tamer.
This plugin is still being updated for Mavericks, however there is a beta version available with Mavericks support.
OmniFocus: Clip-O-Tron 3000 - Included in OmniFocus
Not all Mail.app add-ons come as separate applications. Some Mac developers bundle them to include additional functionality in their applications. Such is the case with the Clip-O-Tron 3000. (I love the name!) You install Clip-O-Tron 3000 from the Clippings section of the OmniFocus preferences. OmniFocus can clip text to store as future task items from a number of applications, but using a special Mail bundle, you have the ability to clip the entire text of a selected email message in Mail.app. The newly created task will have the message's subject line as the title and the notes section of a task will include the text of the original message as well as a link back to the message in Mail.app.
I use the Clip-O-Tron 3000 regularly to create task items from email messages when I'm on my Mac. OmniFocus is smart in that it will link back to the original message, even if it has been moved from the inbox, which allows me to process tasks while keeping my Mail.app inbox tidy. When I'm away from the computer, I also process tasks with OmniFocus from Mail, but to do this I use OmnGroup's MailDrop feature.
This article first appeared in the November Issue of ScreencastsOnline Monthly Magazine. ScreenCastsOnline monthly magazine is packed with hints, tips, articles and links to streamable versions of ScreenCastsOnline tutorials and delivered monthly via Newsstand on the iPad. You can find out more at http://www.screencastsonline.com/magazine/