The word 'grand' is a colloquialism that is unique to Ireland (particularly the north-east) compared to the rest of Europe (and, indeed, the world). Traditionally, the word 'grand' is an adjective used to describe things that are large or somewhat "pompous". In Ireland, however, it is often used in place of the word "good" and its synonyms.
Person A: "Howiya Mick, you keeping well?"
Person B: "Ah yeah I'm doing grand so I am."
As 'grand' is a common word in spoken language, it has inevitably fallen into use in written language, too, and can often be found in non-formal emails, letters, and, of course, IRC.
'Grand' as an adjective has been used on Redbrick IRC for many years, but its use has increased recently due to the increase of students from outside Dublin attending DCU, and growth of activity on IRC by people who join and use Redbrick.
There are various ways to use the word 'grand' in written form, each way resembling how it should be spoken, and corresponding to the level of "goodness" it refers to. These are:
Used mainly in a sentence as an adjective.
This is a grand cup of tea.
I had a grand walk outside in the sun this afternoon.
Often used as a standalone word, outside of a sentence, denoting importance or a sense of completion.
Right, finally got the walls painted. Grand.
I've just been offered a lift to the shopping centre. Grand.
'Grand!' (note the use of an exclamation mark) is used as an expression of pleasant surprise, in cases where the person using it is the beneficiary of something good that has happened, or is happening.
I just won a tenner on a scratchcard! Grand!
My mate just came over with a pizza and some beers! This is grand!
This use is one that can take in all of the above uses combined; covering importance, completion, benefit, and so forth.
Just handed in my FYP there, and I'm finally finished college! GRAND!
I was worried I had AIDS but the doc told me it's only HIV. GRAND!