When you feel a compulsion to acquire a new and shiny gadget. Of course you don't need it, you already have lots and lots of gadgets. But you want something new and you want it in your hands now, to turn over and admire and fondle.
The term originated on the vaping forums. Vaping is the (sometimes obsessive) utilisation of electronic cigarettes.
Examples, each and every one a genuine quote from the forums.
1) Just watch out for the "new" illness... shinyitis... early symptoms creep up on you when you see a nice new shiny bit of kit and suddenly paypal appears on your screen, you lose all control of your finger hovering over the mouse button and then spend the following days wondering why the post is so late as you pace up and down. Beware, there is no cure!
2) That looks good! And it's got the same kind of curved tube as the Picollo, which means the Kayfun should sit nicely on it... Aaarrgghhh! Mad shinyitis!
3) Shinyitis is a disease and a constant flow of shiny tube mods is the cure.
4) Ohh, no. Shinyitis, another excuse to buy a Mech mod.
5) Been vaping for 4 weeks and I am having circulation problems in my bank account......oh hang on, that's shinyitis.
6) I just ordered & am waiting for the chrome one, don't know why... like the idea of the dark chrome also... Ahhh, think I caught shinyitis.
7) Then the shinyitis starts kicking in... amazing how much more pleasure it gives you... waiting for the postie to bring your new purchase.
8) God! Shinyitis is creeping up on me. It's hand is on me shoulder......too late!
9) Shinyitis is addictive... it'll cost ya a bloody small fortune... if you catch the dreaded shinyitis.