[quote name='Doomstink']
Also, the game you've got is a regular old cart, the yellow tab at the top and the unusual shape don't signify anything other than an "unlicensed" cart. Instead of paying Sega for the cartridge shells, they instead opted to make their own. This also required them to put an extra chip in the game to "fake" the Genesis out and think a licensed game was in the system. The extra chip necessitated more space, and thus the cart is bigger than the usual Genesis games.[/QUOTE]
Well, not exactly. Not all unlicensed cartridges had an extra chip in them, and more often than not the extra chip was additional ROM space (ie: two 4mb chips vs. one 8mb). For examples, see some of Ballistic/Accolade's games (like Hardball and Mike Ditka) which fit on the same PCB size as Sega's licensed carts.
The larger cartridge shell was more likely an effort to avoid any sort of patent infringements or legal action on Sega's behalf for possibly trying to pass their unlicensed games off as licensed. The unique size and shape says "Hey, these are unlicensed so don't think we're trying to present them to the consumer as official".
The yellow tab is indeed unique to EA games, and EA continued to use the same case, regardless of PCB size, long after they entered into an official licensing agreement with Sega. Examples would be Populous, the Mutant League games and James Pond, but there are many more. This was likely because EA either still had a lot of empty cartridge shells or because it was cheaper to use their existing assembly lines rather than "upgrading" to standard Genesis cartridges (which they did, but not for a few years).