Rick Nigol recently posted a great message about unnecessary and even exclusionary jargon which is usually counterproductive. It's at least annoying.
Now, I'm not saying we don't get caught up from time-to-time using terminology within a field. Students learning about the Internet and web design surely will encounter terms such as FTP, HTML, server, or CSS. Every field has its lingo, and it can be confusing. One of my colleagues, Dr. Zeitz, deals with this by having his students create a "jargon card", which they hold up if they don't understand a term in class. That way, the group can pause and define the term or use alternative language to clarify.
But when people intentionally use jargon to sell themselves, market a product, or intimidate others--well, that's just annoying, and they should be called on it. Unnecessary jargon excludes and belittles people. It may sell a product to ignorant customers (like negative attack ads in politics), but it doesn't add value to the field or marketplace.