I have been working on a merfolk milling deck for standard environment friday night magic.  The deck has a merfolk tribal theme with control elements to support the decks main focus of milling the opponents deck.  I am looking to tweak the deck at this point and I have no sideboard.  Below is my deck list with comments to follow:

//(Lands)
20 Island

//(Creatures)
3 Merrow Witsniper
4 Cursecatcher
4 Drowner Initiate
4 Ink Dissolver
3 Drowner of Secrets
4 Merrow Reejerey

//(Instants)
4 Broken Ambitions
4 Boomerang

//(Sorceries)
4 Memory Sluice
4 Ponder
2 Distant Melody

After playtesting I found that I didn't have any way to deal with permanents once they hit the board so I added the 4 Boomerang to assist in that area.  Once I bounce the card I can then counter with the 4 Cursecatcher or 4 Broken Ambitions.  The Broken Ambitions also give me another mill option if I win the clash.  I haven't had any problems drawing into milling options with just the 4 Ponder and 2 Distant Melody.  The stars of the deck have been Ink Dissolver and Merrow Reejerey.  You can still attack with your fish each turn as most of the milling are comes into play or pay for abilities.  I do not see any reason to spash any other color.  I want this to remain a milling deck.  I thought adding some other counters in the sideboard or more draw may be an option.  Please post any comments, suggestions or questions for the main deck and sideboard.  Thank you for taking the time to read through this.


--EDIT--

After reviewing comments for this post I am now trying out the following deck list:

//(Lands)
10 Island
10 Plains

//(Creatures)
3 Judge of Currents
3 Cursecatcher
3 Drowner Initiate
3 Ink Dissolver
3 Drowner of Secrets
3 Merrow Reejerey
3 Stonybrook Schoolmaster
2 Grimoire Thief

//(Instants)
2 Broken Ambitions
3 Oblivion Ring

//(Sorceries)
3 Memory Sluice
3 Ponder
3 Distant Melody

//(Enchantments)
3 Merrow Commerce

--EDIT--

My third incarnation of this deck has to run lots of three ofs because there are just so many cards that work in this deck:

//(Lands)
3 Wanderwine Hub
9 Island
9 Plains

//(Creatures)
3 Judge of Currents
3 Cursecatcher
3 Drowner Initiate
3 Ink Dissolver
3 Drowner of Secrets
3 Merrow Reejerey
3 Stonybrook Schoolmaster
3 Grimoire Thief

//(Instants)
3 Sage's Dousing
3 Dream Fracture
3 Oblivion Ring

//(Sorceries)
3 Ponder

//(Enchantments)
3 Merrow Commerce

It is still Blue with a White splash.  It is milling with control support.  I think there is still more that could be done to focus the deck but I have not been able to get in enough playtesting to determine where the focus lies.  Thank you all for the suggestions and assistance in making this deck better.

--
Soundwave42

I built an affinity deck back during the Mirrodin block that is all commons/uncommons and 2 rares:

//(Creatures)
2 Broodstar
4 Frogmite
4 Myr Enforcer
4 Somber Hoverguard
4 Steel Wall

//(Instants)
3 Thirst for Knowledge
3 Shrapnel Blast

//(Sorceries)
4 Thoughtcast

//(Artifacts)
4 Tooth of Chiss-Goria
4 Pyrite Spellbomb

//(Equipment)
4 Bonesplitter

//(Lands)
4 Seat of the Synod
4 Great Furnace
4 Ancient Den
4 Vault of Whispers
4 Islands

I left the game for 2 years then came back This year with Lorwyn.  This was the only deck I had left completely constructed.  I started playing with it in my casual group and its still as good as it ever was for quick fun beats.  The affinity mechanic is still one of my favorites to play.  I don't think I will ever take this deck apart.