This addon filters out the debuffs and buffs that you don't care about, and places them anywhere on screen. If you're a melee class, you can filter out everything but CoR, FF and Sunder. If you're a caster, you can just show debuffs like CoE and Winter's Chill. Healers can filter out everything but their buffs and HoTs, etc.
This addon can also display cooldowns. It can show all listed cooldowns, or it can show spells and items that are not on cooldown and that are available for use. You can also make these cooldown buttons clickable. In other words, you can create more toolbars.
Besides filtering your current target, you can filter buffs/debuffs on yourself, and buffs/debuffs on the Focus target. Buffs/debuffs are grouped into frames. You can duplicate frames, so you can have more than 1 frame for your target. You can also create frames for other valid targets, like pet, raid1, targettarget, etc.
To configure the mod once it's installed, type /dfilter -- you should see a simple UI. To add a filter, select "Frame Buffs" on the left hand side, then select your target from the dropdown menu (Target, Player, Focus), then select the Buff or Debuff tab, then type in the name of your buff/debuff and press enter. You won't see the list of buffs/debuffs unless you enlarge the window, which you can do by dragging the bottom right corner.
If you're not sure how to set the Focus target, you can either type /focus <target> or go into keybindings and bind keys to "Focus Target" and "Target Focus" under Targeting Functions.
Note: make sure "Show Frame" is checked for your target type, or you won't see anything get filtered.
To move the frames, select "General Settings" on the left hand side, then check "Show Backdrop", and then shift-click and drag one of the backdrops.
If you'd like to change the orientation of any frame, select "Frame Layout" on the left hand side, then select the direction under the dropdown Grow menu, and then configure how many buffs or debuffs you'd like to see per row. The layout settings are as follows:
Right-Down, Right-Up: grows to the right, new rows start below or above the first row.
Left-Down, Left-Up: grows to the left, new rows start below or above the first row.
If the "rows" setting is set to 1, you'll have vertical orientation.
To change the orientation of the buff duration time, ctrl-right click the frame you'd like to configure.
Settings are stored on a per-character/server basis, so it should work fine if you have alts.