Grey text in subject line.

[Make7]

2. That happens in LBN if you start typing the subject line before the page fully loads.

There is some javascript that loads when posting to LBN that makes the prompt text grey in the fields for article, link, and source - the text changes back to black when you type/paste in the required data.

Even though that script is written for opening posts, it also runs when posting replies in LBN. Usually it has loaded and run before you start typing the text for the reply title - so nothing really happens - but if you start typing the title before the script has run (when the page has completed loaded) then the text turns grey when the script executes.

Shorter answer: it doesn't really mean anything - it's a minor glitch from a script used when starting LBN opening posts that also happens to load when posting a reply.