Gilspam.. ugh! :X

[Morbid]

As a fellow player on Jenova I feel your anguish. Best bet is too go on /busy status pretty much all the time. You'll have to remember to drop busy status to get into a party for something like Hunts of Fate groups. Also might want to drop it before going into raids if you want to see the 'Ready Check' prompts.

If you don't like having the red busy face up all the time the next option is muting or changing the PM notification sound to something less aggravating and moving /tell to its own window.

As far as blacklisting. Try not to blacklist after one message find the ones that send multiple tells in short spans and messages from multiple names advertising the same site.

Other than that not much you can do to combat it. Just deal....