Here are some of the highlights....
Retailers capitalized on -- um, I mean, commemorated -- the inauguration of President Barack Obama, using a variety of angles in their email messaging.
Executives finally realized that email marketing is a powerful, inexpensive marketing channel. Some then began making unreasonable demands of a channel they didn't understand.
During their last chaotic days, both Circuit City and Linens 'n Things sent emails that weren't CAN-SPAM-compliant because they lacked mailing addresses and/or unsubscribe links.
Overstock.com introduced a progressive couponing scheme as part of its St. Patrick's Day promotion in a March 16 email. Overstock later used the same scheme in a 4th of July promotion.
Marketers ratcheted up their recession-conscious messaging, which was best exemplified by "Save Now" replacing the "Buy Now" call-to-action.
Leveraging a tie-in with the movie Monsters vs. Aliens, HP used a breakout design featuring Ginormica in a March 30 email.
Coach launched a redesign of its email template in an April 2 email, adopting a vertical navigation bar. The company is the only major online retailer to rely solely on a vertical nav.
Blair and J&R ran Easter egg hunt campaigns that encouraged customers to browse Web sites until they found hidden eggs that contained discounts or prizes.
Due to a glitch, Gmail disabled images in emails from all senders, even those that were whitelisted by recipients.
Video gifs caused a stir after they were used by eBags and Overstock.com -- and then they all but disappeared from use the rest of the year. What was expected by many (including me) to be a big trend for 2009 was almost a non-event.
Circuit City and Linens 'n Things returned from the dead under new ownership and with new email templates.
In a May 27 email, Buy.com promoted its Tweet n Seek game, which required players to follow the company on Twitter, search Buy.com, visit its Facebook page, and read products pages. It was a clever way of exposing customers to many of Buy.com's marketing and sales channels.
Drs. Foster & Smith launched a "Pet Tails" email series with a June 10 email, leveraging tests that showed promotional content performed better when it followed, rather than preceded, education content.
Hallmark sent the first Christmas email of the year on July 1.
Microsoft announced that Outlook 2010 would suck as much as Outlook 2007 sucks.
Abercrombie & Fitch discovered the sidescrolling email -- and went crazy with it, adopting it as the company's standard format.
MySpace launched an email inbox product, giving us yet another environment to worry about emails rendering properly.
Walgreens introduced a visual navigation bar to its Aug. 7 email, making it one of only a few major retailers that include icons in its navs.
Despite all the buzz around SWYN, only 12% of major online retailers included links in their emails that allowed subscribers to share the email with friends and family on one or more social networks.
ISPs started using engagement metrics to determine inbox placement. Email lists everywhere groaned a little louder under the tremendous weight of their inactive subscribers.
Amazon.com had marketers scratching their heads when the company announced in a Sept. 2 email to subscribers that it's discontinuing its Hot Deals in Electronics newsletter and moving the deals over to a Twitter account.
Banana Republic, Overstock.com and ShopNBC sent emails leveraging the date 9/9/09. Overstock explained, "This is the last time there will be single digits in the month, day and year for next 1001 years."
Google Wave was released and it wasn't that great. The Twitterverse echoed with people trying to unload extra Google Wave invites. Anyone? Anyone?
Without a peep, subscribers stopped receiving EB Games branded emails and started receiving ones from sister brand GameStop.
Lands' End debuted the BigWarmUp, a coat collection drive that used email to spread its viral video message. The big wow came when recipients saw that their names had been dynamically inserted into the video. [Cue tears.]
Zappos sent subscribers an email that explained that the company would be sending more emails during the holiday season, and on which days to expect them. Transparency takes one small step forward.
Before the midway point in November, more than three-quarters of major retailers had sent at least one email referencing the holidays.
Black Friday messaging was twice that of 2008.
Cyber Monday became the most popular day of the year to sent retail email, with 71% of retailers sending at least one email.
Looking to make its emails more actionable, more than 10% of retailers included discount codes in its preheaders.
Harry & David sent a Dec. 2 email dedicated entirely to Hanukkah products. No more than a handful of major retailers make any kind of direct, visual or date reference to Hanukkah.
The Canadian Tourism Commission had email designers everywhere saying, "Why didn't I think of that?" when it sent a fantastic email that requires subscribers to scroll right, left, up and down to get to the call-to-action.
A&F veered ever closer to softcore porn with messages like this Dec. 3 email.
Overstock.com was the first retailer to mention the Droid mobile operating system in an email during a year when roughly 10% of major retailers promoted iPhone apps in its email marketing campaigns.
Retail email volume hit an all-time high, with retailers sending 4.1 promotional emails per subscriber on average during the week ending Dec. 18. During that week, Brookstone sent subscribers 21 emails, besting the previous weekly volume record by 50%.
What do you consider the other big events of the year?