I saw on neilgaimanboard.com some one suggesting the following:
The "forgettable god" should be Mercury.
More explicitly, the "forgettable god" should be a Hindu deity named <PERSON>, the son of the moon god Soma and <PERSON>, the wife of <PERSON>, or <PERSON>. Budha is one of the navagraha (literal nine-planets), or planet-gods in Vedic astrology; to the ancient Roman, he is Mercury.
Much like the Roman Mercury, the Hindu Mercury is a god of two things: wealth and the mind.
He governs commerce, both tangible and intangible; he grants wealth on to his devotees; he removes obstacles in the way of success.
As the god of knowledge, it is <PERSON>'s power to both grant and erase wisdom. The "greatest among the wise," he has the ability to remove thoughts from minds as well as grant inspiration.
The "forgotten god" is a dark-haired, dark-eyed, well-manicured man. <PERSON> had dark hair and dark eyes, and was considered to be the most attractive of the navagraha.
Now is were we really get analytical:
The element mercury, also known as quicksilver, is the only metal that is liquid at room temperature. It is notoriously difficult to contain and is extremely quick to evaporate; the phrase "like trying to hold mercury" is a common euphemism for things which are either easily forgotten, or difficult to contain.
The "forgettable god"'s home is Las Vegas, which <PERSON> goes out of his way to describe as a place where money evaporates or melts away, just like all knowledge of the "forgettable god."
If Mercury is both the incarnation of money and knowledge, and mercury is also impossible to contain or retain, you get ... knowledge and wealth that is impossible to contain or retain. The forgettable god.
More details:
The forgettable god wore what <PERSON> referred to several times as a "charcoal suit." The only thing that can contain or absorb liquid mercury is charcoal, which is utilized in containers designed to control mercury spills.
Wednesday orders the forgotten god a Laphoraig and water while they're at the bar. 722
Laphoraig is an Irish single-malt whiskey famous for its peaty aroma, partially the result of a brewing process that involves peat from the local peat bogs. Mercury is a natural byproduct of peat.
Gaseous mercury is used to create neon lights, which <PERSON> notes numerous times are the hallmark of Vegas.
While I've already noted it, I think it's important to restate that <PERSON> was the son of <PERSON>.
Finally, the Hindu word for Wednesday is derived from <PERSON>'s (<PERSON>'s) name, just as our word for Wednesday is derived from <PERSON>'s name. This may further explain why <PERSON> made <PERSON> the "forgotten god" - because the book already had a Wednesday. (It also explains <PERSON>'s use of the song titled Why Can't He Be You - think about it for a minute - during the scene in the bar when Wednesday and <PERSON> meet, and why <PERSON> chose to describe the two in such similar terms during that scene.)
I think this suggestion is the closest to what I have seen, so I am going with it.
I have found that the person that have stated the aforementioned has also posted the following:
I'll add that, upon further consideration, I think that "the forgettable god" is supposed to be an embodied combination of all of the different Mercurys: the planet Mercury, the element Mercury, and the Hindi and Roman gods Mercury (who are virtually identical), with a strong leaning toward the Hindi Mercury (which is why Wednesday can bribe him with soma, and why he has dark hair and dark eyes).
The only Mercury that isn't consolidated into the forgettable god, though, is Wednesday. <PERSON> is the Nordic equivalent of Mercury. (For more connections, as I noted, the Hindi word for Wednesday is derived from <PERSON>'s name; furthermore, the French word for Wednesday is Mercredi, which comes from the word ... well, I'm sure you can figure it out.)
Wednesday (<PERSON>) is the only <PERSON> who isn't a god of commerce, which is I think the reason why he is separate from the other <PERSON>. 321