Digital marketing seems to have so many abbreviations - so I've put together a list. As with any industry there's always the expected jargon, but marketing seems to have more than most, so here is a list of the one's I've heard of so far, and if you know of any which I've missed them add them onto the comments at the bottom.
Augmented Reality - Normally you wave your smartphone around a physical location and your scenery is 'augmented' by extra features from the computer, like videos and sounds. Have a look here for examples of how it's being used.
Content Management System - A CMS is a program which runs on the back end of many websites which allows people to login and add, edit and change content without having to manipulate the actual code of a website. They make life a lot easier.
Cost Per Click - If you set up a paid campaign, (like Google Adwords) then you need to know how much it's costing you each time someone clicks through to your webpage. It's also connected to PPC (Pay per Click).
Cost Per Impression - Very similar to CPC, Instead of direct click through's, cost per impression is the price you would pay for an online ad campaign depending on the number of times your advert is displayed.
Customer Relationship Management - Normally a database or piece of software which manages a companies interactions with it's client's right through the entire sales process.
Conversion Rate Optimisation - If you get visitors to your website you'll want them to do something - buy a product, phone you, download an ebook etc. CRO involves studying the data and making improvements to increase the number of conversions. There's an awesome post of how to do this on SEOMoz.
Click Through Rate - A percentage or figure for how many people are literally clicking through from one item to another. It's normally mentioned with regards to email marketing or PPC advertising.
Domain Authority - A score used by SEO Moz which is much the same as Page Authority (see below) which measures the strength of an entire domain to predict how well a site may appear in search engine results. The score given is from 1 - 100, but is logarithmic so getting from 25-35 is going to be much easier than going from 65-75. More information about it here.
Direct Message/Direct Mail - A message which is normally sent behind the scenes of most social networking sites, like Facebook and Twitter, so you can contact someone privately on the site without everyone else seeing.
Instant Messaging - A way to chat with someone over the internet through a pop up text box which allows for real time conversations. It's particularly useful for businesses to chat with their customers quickly and easily.
Page Authority - A calculation from the guys at SEO Moz which calculates how well a single web page will rank in search results, regardless of its content. It's similar to Domain Authority (see above). A webpage gets a score from 1 - 100 but it's logarithmic so the higher the score the harder it is to obtain. Exact details here.
Pay-per-Click - Connected to Cost per Click (CPC) PPC is a form of advertising where by businesses can pay to have their website appear on search engine result pages or other websites. They only pay when someone clicks on the advert.
PageRank - A score from 1-10 that Google assigns to your website, based on a whole variety of factors. The higher the number the better the site, but there's a whole lot more to it than that, so have a look here for the full details.
Quick Response (Code) - A small square barcode which are used in offline marketing materials - You've probably seen them before. If someone has a smartphone they can scan the QR code and be taken to a specific page, video or website. If you want to make you're own use QR Stuff (it's free!) but have a look through here first for ways of not to use them.
Really Simple Syndication - A web feed format which is able to provide people with a summary about recently added content (like new blog posts). People using a RSS Reader can then subscribe to multiple RSS feeds and have a ready source of information that's updated whenever something new comes along.
Re-Tweet - A Twitter term. If someone Re-tweets you they share your message with their followers, expanding the potential reach of your tweet.
Return on Investment - A proper business term which has been around for a long time. It's the process of going through the data to try and work out if the resources you've put towards a business goal have had the intended outcome - and you guessed it, meant you've made a return on your investment.
Search Engine Optimisation - The tools and processes that can be applied to make a website appear more highly in search engines result pages (in a very brief nutshell). To start learning about SEO, have a look at the fantastic beginners guide to SEO.
Search Engine Results Page - Pretty clear really, but most people write SERP's as it's easier to say and write than Search Engine Results Pages each and every time.
Social Media - Twitter, Facebook, LinkedIn, Google +; Social media is a term used to describe these types of social networking sites as a form of media alongside things such as print and TV. The phrase SM isn't all that often used, but it's added just in case you wondered.
User Interface - The area where a person interacts with a machine or device. There's a lot of work that goes into this sort of thing to study how people interact with items and how they can be improved.
User Experience - The study and improvement of a website to give a visitor the best possible experience when they visit. This includes consistent design, easy navigation great copy etc to increase your business objectives and leave the customer happy.
What You See is What You Get - Most of the time this is a user interface where you add something, and it closely matches the finished product. This makes life a whole lot easier as you don't have to write something and constantly check the result to see if it looks alright.