What is up with these release Dates???

[Stellar]

I have looked at the benchmarks on all these kool new Video cards, and most are pretty easy to understand, (with the help of term definitions provided by this great website). But the Release dates are really confusing, Whats "H3 99" and G4 and stuff. What does that all mean? (i figured that the 99 and 98 are the year, duh)

[collinj]

Usually what you will see will be the following:

H1 = first half of the year
H2 = second half of the year.

Q1 = first quarter of the year
Q2 = second quarter of the year, and so on.

I dont know about "g", I have never seen it.
Usually you will see something like: Q398 or like: Q199. If you see something like: H199, the manufacturer has only a general idea of when it will be released, thus the 6month span. They are just guessing.