Web Traffic - Web traffic is simply how busy your website is; how many people come to your website regularly.
Search Engine Optimization - SEO for short, refers to the practice of making your website or blog as easy to find by search engines like Google and Yahoo as possible. It involves using the right keywords in your text and in the code of your website or blog. Keywords that your ideal site visitors would use to find you. It involves placing the right things in the right places in the code of your website. It involves titling each individual page in your website or blog correctly.
Search Engine Marketing - SEM for short, refers to creating a marketing campaign for your website or blog based on how effective your website or blog can be found through search engines. It involves SEO as one component and may include pay-per-click campaigns using Google Adwords where you pay Google each time your ad (which you created using Google) is click on when Internet users are searching the Internet. Learn more here at Wikipedia.org.
Google Adwords vs Google Adsense - With Google Adwords you create ads for you or your company. Google publishes them and they come up in Google (and other) search engines when the appropriate keywords are used. When someone clicks on the ad, you pay Google a certain fee. Google Adsense on the other hands are ads you place on your website or blog that Google pays you for if your site visitors click on them.
RSS - RSS is a simple way of publishing constantly updated or changing content. RSS is the foundation of blogging. An RSS feed is the URL which you can copy and paste into an aggregator (like Bloglines or Feed Reader) to collect numerous articles from numerous blogs in one location. Visit What is RSS?, an excellent source on explaining in more detail the wonders of syndication.
Web Copywriting - Web copywriting is writing copy specifically for the web. Usually web copywriting is written to convince site visitors to perform a certain act such as buy a product, subscribe to a service or call or email a company, etc. Web copywriting is basically ad copy for the Internet. The way people read the Internet is not necessarily different from the way they read ads in print, but web copywriters know how to write in keywords and focus on keyword density as much as the right language to use to be convincing. Though, Internet copy does need to be a bit more concise and much more convincing since there are millions of websites out there and users can visit about a hundred or more in a day versus newspaper or magazine readers who’d really only read a handful at the most a day.
HTML - HTML (Hypertext Markup Language) is the basic code used to create the structure of web pages. XHTML is the new HTML in a sense and stands for Xtensible Hypertext Markup Language. The idea behind it being that XHTML is supposed to be more semantic than HTML. Semantic meaning that the coding (the tags) used to define the structure and layout of a page has more meaning to what it’s being asked to do. For example, <b> stands for bold. You use this tag and it makes a word or letter bold. In XHTML, <strong> replaced <b> in HTML. The word strong has more meaning. The goal I think in making web coding more semantic is to make web pages more universally compliant and relevant so that all browsers can translate them. The web is moving away from 00100100 Matrix type language to more meaningful language for easier implementation.
CSS - CSS (Cascading Style Sheets) is the styling code used to create the layout and look of web pages. Instead of using HTML table, you use CSS class divisions to represent the layout of web pages. Agai, this is more semantic since “tables” and the “columns” and “rows” used to create them don’t really “mean” anything, where are “divisions”, “positions” and “paragraphs” do.
Web Designer - Usually a web designer only designs the look of the web page and hands it over to the web developer. But more and more, a web designer “DESIGNS” in the traditional sense, which includes building the structure as well as just designing the look of it.
Web Developer - A web developer turns a web design into an actual website or blog.
Web Programmer - A web programmer does the heavy lifting. A web programmer is responsible for how well the website functions. Usually web programmers know a few programming languages like PHP, Ruby, C++, etc, or they know one really well.
IT - Internet Technology is exactly what it says. IT is the technology behind how the Internet works.
I think this covers much of the common terms that are webcentric these days. I’d love to heard any suggestions on adding others.