What does this guitar tab symbol mean?

[canadaski]

I've come across this but am not sure how it is played. What does that thing with the line through it mean?

http://desmond.imageshack.us/Himg843/scaled.php?server=843&filename=notyes.png&res=medium

[Jimmy Page]

It means legato slide

[kenoloor]

It means legato slide

Also known as a glissando, yes.

[Mortal Coil]

That means you slide but don't strike the second note, just in case you were still confused :)