Every industry has its acronyms. With this list you will be prepared when dealing with people who speak digital:

AIDA - Attention, Interest, Desire, Action

AJAX - Asynchronous Javascript and XML

API - Application program interface

AOV - Average order value

AR - Augmented reality

ASP - Application service provider

ATD - Agency trading desk

B2B - Business to business

B2C - Business to consumer

CIO- Chief information officer

CLV - Customer lifetime value

CMS - Content management system

CPA - Cost per acquisition / action

CPC - Cost per click

CPL - Cost per lead

CPM - Cost per thousand

CPV - Cost per view (see also PPV)

CR - Conversion rate

CRM - Customer relationship management

CRO - Conversion rate optimisation

CSS - Cascading style sheets 

CTA - Call to action

CTR - Click-through rate

CX - Customer experience

DM - Direct mail (or 'Direct message', in Twitter circles)

DMP - Data management platform

DNS - Domain name system

DR - Direct response

DSP - Demand-side platform

ECPM - Effective CPM

EPC - Earnings per click

EPM - Earnings per thousand

ESP - Email service provider

FAQs - Frequently asked questions

FB - Facebook

FBML - Facebook Markup Language

FTP - File transfer protocol

GA - Google Analytics

HIPPO - Highest paid person's opinion

HTML – Hyper Text Markup Language

HTTP - Hyper Text Transfer Protocol

HTTPS - Hyper Text Transfer Protocol Secure

IM - Instant Messaging

IMAP - Internet Message Access Protocol

IP - Intellectual property (or 'Internet Protocol')

IPTV - Internet protocol television

ISP - Internet service provider

KPI - Key performance indicator

LTV - Lifetime value

MoM - Month on month

MLM - Multi-level marketing

MVT - Multivariate testing

OEM - Original equipment manufacturer

OS - Operating system (sometimes this is used for 'open source')

PHP - PHP Hypertext Preprocessor

POP- Point of purchase

POS - Point of sale

PPC - Pay per click

PPL - Pay per lead

PPV - Pay per view

PR – Page rank

PV – Page views

QA - Quality assurance

QR Code - Quick response code

QS - Quality score

RFI - Request for information

RFP - Request for proposal

ROI - Return on investment

RON - Run of network

ROR - Ruby on Rails 

ROS - Run of site

RSS - Really Simple Syndication

RT - Retweet

RTB - Real time bidding

RTD - Real time data

S2S - Server to server

SaaS - Software as a service

SEM - Search engine marketing

SEO - Search engine optimisation

SERP - Search engine results page

SLA - Service level agreement

SM - Social media

SME - Small / medium enterprise. (aka SMB = ‘business’)

SMM - Social media marketing

SMO - Social media optimisation

SMP - Social media platform

SMS - Short message service

SOV - Share of voice

SOW - Statement of work

SSL - Secure Sockets Layer

SSP - Supply-side platform

SWOT - Strengths, weaknesses, opportunities, threats

TLD - Top level domain

TOS - Terms of service

UCD - User-centric design

UI - User interface

UGC - User-generated content

URL - Uniform resource locator

USP - Unique selling proposition

UV - Unique visitor

UX - User experience

VOD - Video on demand

VM - Viral marketing

WC – Week commencing

WOMM - Word of mouth marketing

WYSIWYG - What you see is what you get

YOY - Year on year

YTD - Year to date

XML - Extensible Markup Language

I'm sure we've missed a few. Feel free to add your favourites in the comment box.