Here are some definitions of some terms used in WWS reports :

* Presence : This is the percentage of the player presence versus the raid length. Someone who arrived or left at the middle of a raid will have a 50% presence. If someone dies at 2/3 of a fight, she will have a presence of 66%.
* DPS Time : The DPS time is based on a 5 seconds window following every damage done. If someone performs damage every 5 seconds or less, her DPS time will be 100%. If for some reason she must stop to DPS for a short time, her DPS time will be lower. Tanks usually have the best DPS time because they're always close to the boss.
* DPS or Instant DPS : DPS is the damage done divided by the DPS time. It is a measure of how strong a player is hitting when she is hitting. Some people can have very high DPS but very low DPS time, ie a healer who performs only one single powerful attack during the fight : very short DPS time but very high DPS.
* Average DPS : The average DPS is the damage done divided by the presence. Generally, this information is less relevant than Instant DPS because it provides no real additional information over the total damage done.

Hanshi, I throw this out only as an example to your question of how can my damage be lower if I'm doing x dps.

This is from the wws log for the first wave before rage...so very beginning of damage for the night.

20:41'54.278 First damage done - Trix, avengers shield to initially get aggro
20:42'01.219 My pet first attacks a mob
20:42'02.812 Papa starts Holy Nova aoe (doesn't cause threat)
20:42'05.228 I start volley aoe
20:42'08:380 Hanshi starts aoe

So my pet started doing damage about 7 seconds after pull
Papa started doing aoe damage 8.6 seconds after pull
I started doing aoe damage 11 seconds after pull
You started doing aoe damage 14.1 seconds after pull
Between myself and my pet I had a 7 second damage head start over you. Granted my pet is only doing a third of my damage, but its still relevant. I had a 3.1 second head start on my aoe. Three seconds at say 2k dps is a 6k damage headstart. Times that over the 8 waves and that's 24.8 seconds or 48k damage headstart if i'm consistently starting dps earlier. Times that by 4 bosses and were talking 96 seconds or 192k damage. And these numbers don't reflect the 4 second damage headstart my pet had on me, which would be something like 2.4k damage per wave. Plus, im sure there are other headstarts, like the md damage that I get to apply before everyone else each boss attempt.

Point im trying to make is that it's the accumulation of all these little numbers that make the big picture.

Keep in mind, almost all of us did much better in Hyjal then we ever had before. Our damage and dps was way higher then before. One day after the patch with all the addon issues and spec unknowns, I think that is pretty darn good.

Excellent post by both Piper and Mstar here.
High dps comes from your gear, spell rotation, and buffs. That's the easy part right? Do your research, get the best gear you can, enchant and gem it for the best dps, learn the highest dps spell rotations for raiding..... etc...
Now comes the fun part! Turning that dps into damage. This is the part that requires skill and makes our role in the raid exciting. Mstar's example if very good here and I'll try to expand that a bit more. The key is to get as close to the Tanks threat as possiable WITHOUT going over and pulling aggro for the longest time possible. Inversly the more THREAT the tank can put out the more damage the raid can do. But what if you are never coming close the the tanks threat level? Then you are underperforming per your gear level and thus doing less damage than you could have for a given fight.
Thats not to say that everyone should be at 99% of the tanks threat because the tank may get stuned or we may get a big crit and then BAM dead dps and blown healer mana tring to keep your stupid arse alive!
The goal is to know the fight mechanics and your own threat fluctuation verses the tanks threat ups and downs for a given boss and stay as high as you SAFELY can. This is how more skilled players out damage less skilled players with higher dps Now go get em!! And watch that threat meter!!

Remember that damage done is more important that DPS. You could spike your DPS then die.. and that is pretty useless.

Silvyr made a good point as well. The meters only tell half the story. Most DPS classes have a secondary role which is equally if not more important. CC, off tanking, off healing, cleansing, decursing, battle rezing.... All these take priority over DPS and don't show on damage meters.