DHTML
It really bugs me when people still talk about DHTML.
"Oh, I know DHTML."
No, you don't. There is no such thing as DHTML - it is another pile of marketing rubbish. There is HTML / XHTML, CSS and JavaScript / ECMAScript. Anyone caught still referring to DHTML today really needs to catch up - it's a term on a C.V. which would make be bin it (I might write a separate post on that - terms that I would automatically detect in a C.V. using a filter to instantly bin them).
The term AJAX I can accept - although if people tell me they "know" AJAX that is also annoying. AJAX isn't a language, it's more a technique using a combination of existing technologies (and facilitated by something Microsoft came up with quite a while ago).