Below is our weekly leaderboard of Facebook games with the most daily active users. This is a metric we’re looking at more closely, because it gives a better view than monthly active users of how engaging — and potentially lucrative — an application is. The more often users come back to play a game, the more likely they are to decide to buy or earn some virtual currency.

For games that have already proved successful, the next useful step is to divide DAU by MAU, which gives a stat we’re calling stickiness — how many new users a game tends to retain. Check out this post for a full explanation of stickiness.

Big Fish

For a second week in a row, Zynga’s Fishville is king of the DAU chart. The top five now includes two other fishy apps, Fish Isle, by IGG, and Happy Aquarium, by CrowdStar, while Fish Life comes in at #17.

But if DAU is any indication, Fishville and Happy Aquarium have become the Poseidon and Triton of Facebook (father and son amphibious gods, for those not up on their Greek mythology). Fish Isle is still small fry, while the DAU growth of almost every other fish app has slowed considerably.

Last week, we asked how big Fishville can get — at the time it was shooting past nine million users, and is now almost double that. Could it catch up with Happy Aquarium? It still may.

But while Fishville’s MAU has continued to skyrocket, its DAU growth isn’t as rambunctious as it was, and the app’s stickiness has fallen to 36%. Its growth may pick back up after Thanksgiving, but if it doesn’t, Happy Aquarium will probably maintain its lead. Here are the rankings:

	Name	DAU	Gain	Gain, %
1.	FishVille	6,302,573	+1,148,805	+18.23
2.	Happy Pets	1,357,897	+541,826	+39.90
3.	Café World	10,319,129	+431,134	+4.18
4.	Fish Isle	353,081	+300,951	+85.24
5.	Happy Aquarium	7,974,860	+255,647	+3.21
6.	Farm Town	5,481,339	+230,973	+4.21
7.	Champions Online	148,666	+148,649	+99.99
8.	Texas HoldEm Poker	4,489,307	+115,527	+2.57
9.	Island Paradise	1,922,376	+87,014	+4.53
10.	Crazy Planets	257,451	+51,220	+19.90
11.	Castle Age	618,517	+43,535	+7.04
12.	The Hierarchy	55,013	+28,779	+52.31
13.	Tarjetitas	98,050	+25,716	+26.23
14.	Ninja Warz	56,853	+23,250	+40.89
15.	Do you think…?	44,993	+22,062	+49.03
16.	Icy Tower	122,095	+17,371	+14.23
17.	Fish Life	503,160	+16,131	+3.21
18.	Name Analyzer	25,971	+15,858	+61.06
19.	My City	121,107	+14,621	+12.07
20.	Piou Piou contre les cactus	54,654	+14,412	+26.3

Among the lower rankings, you might notice some apps that are slowly gaining a loyal userbase. They’re conveniently ranked #9-12: Island Paradise, Crazy Planets and Castle Age. While Crazy Planets is a bit below the success threshold with only 13% stickiness, the other two are in the 20-30% range that indicates they may be long-term winners.

The rest of the rankings are a mixed bag of game types, and most are new this week. Given the holiday, we’ll probably have to wait until next week to see whether any of them really have traction.

This is a guest post by Chris Morrison