The icons are sorted associatively, not alphabetically, as follows.
Row #1 are the miscellaneous forum wide icons.
Row #2 are the event icons as well as the start of the subject icons
Row #3 has the last three subject icons and the press related icons.
Row#4 has all the setting icons
Row#5 has all the sci fi icons.
Row #6 has a couple more misc icons and the D&D topics icons
Row #7 are all D&D topics.
The idea behind this sequence is that related icons behing in groups helps locate them. I'd rather leave this sequence alone, for now. I'm looking into a hack that puts the post icons into a pull down menu that will be grouped into topic fields and then alphabatized, sorta like the subject icons. This trick is somewhat low on my list of priorities for the moment, but it will be done (part of it's advantage will be relieving dial up users of the need to load all icons when they start a new message).