The character(s) resulting from hitting the backspace key VT100 terminal emulation. Used in electronic conversation in a playful connotation, typically by sysadmins or old UNIX heads when speaking of a moronic user (a.k.a. luser) by typing l^Huser

Yep. One might also note that it's Ctrl-H.

excerpt from the jargon file:

There is also an accepted convention for `writing under erasure'; the text

Be nice to this fool^H^H^H^Hgentleman, he's visiting from corporate HQ.

reads roughly as "Be nice to this fool, er, gentleman...".
This comes from the fact that the digraph ^H is often used as a print representation for a backspace.
It parallels (and may have been influenced by) the ironic use of `slashouts' in science-fiction fanzines.

The single character version of ^W, which people don't use as often in denotative text because a lot of people don't know about it.