I'm a bit confused over what exactly is a HUD as it relates to poker. I'm a retired technologist/military officer and to me a HUD is a Heads Up Display which is a piece of hardware that 'floats' an image in front of you while you are looking at something else. Used a lot in aircraft, weapons systems, autos ect. Kinda like Google Glasses.

http://en.wikipedia.org/wiki/Head-up_display

When people say that they use a poker HUD, I *think* they mean that they are using an add-on piece of software that intergrates with a poker site's client's software that displays stats on the other players in real time, pulled from a database of past performance by that player, right? Sorta like a plug-in for Photoshop. They are not using a 2nd display piece of *hardware*, are they?

When some-one says that a poker site doesn't alow the used of a HUD they mean that the site's client software does not alow plug-ins, correct?

I guess I'm over-engineering this but to me a HUD is a piece of hardware not a software plug-in. Sorry if this is a dumb question. TIA!

Separate application / separate piece of software.

Thanks! So how does a site like Bovada prevent them/ban them from working? How can they tell that you are running one if it's not part of their client software?

Bovada prevents them by anonymity - there are HUDs for Bovada but they can't retain stats beyond a single table session.

Ah!!!!!! Now I'm begining to understand. The HUDs are vectoring in on the existing client display to add their stats to the client's screen. Hence the term "HUD".

I appreciate the help. Thanks!

Poker is a game of information ... and a lot of people will do anything for an edge in the online poker realm. Hence HUDs, seating scripts, table scanners, bum hunting.