Disney's ABC competes with CBS and Comcast NBC for ratings supremacy, but that's not the entire story

Remember this? Coulson & Captain America in Marvel's The Avengers. Credit: Marvel

Given the widely anticipated U.S. debut of Disney (DIS -0.28%) Marvel's Captain America: The Winter Soldier this weekend, at first it seems silly to focus much attention on tonight's TV ratings for Marvel's Agents of S.H.I.E.L.D.

After all, as fellow Fool Leo Sun argued last month, the importance of Agents of S.H.I.E.L.D.'s ratings might pale in comparison to its ability to act as an effective advertising tool for Disney Marvel's hugely profitable ventures on the big screen.

Ratings still matter...
But that won't stop short-sighted industry pundits from chiming in when the numbers for tonight's new episode become available tomorrow -- especially if Agents of S.H.I.E.L.D. can't improve on its most recent 2.1 rating with adults 18-49 on 6 million live viewers, a result achieved with the help of Lady Sif during its last original telecast three weeks ago.

Meanwhile, Comcast (CMCSA 1.20%)/NBC's The Voice once again dominated the night with 13.14 million live viewers and a 3.4 rating. Heck, even a rerun of CBS' (PARA -2.42%) NCIS garnered an impressive audience of 10.79 million -- though the less-valuable composition of CBS' viewership was only enough to achieve a 1.3 rating for third place in the core 18-49 demo.

But when you look deeper, it becomes evident Agents of S.H.I.E.L.D. has already proven a big winner for Disney's ABC. In addition to finishing its last episode as the No. 1 scripted series in its slot for the 15th consecutive original telecast with men 18-34, Agents of S.H.I.E.L.D. goes into tonight's episode having improved its time period by 60% for ABC over last year.

Considering Disney specifically cited ABC's lower overall ratings as a weak point in its most recent quarterly report, it would appear Agents of S.H.I.E.L.D. stands out as an overachiever for the television network.

...but so do Marvel's films
At the same time, I think it's fair to expect the buzz surrounding Winter Soldier's impending launch to provide a nice TV ratings boost for Agents of S.H.I.E.L.D. tonight, but you can be sure the show's creators are aware it isn't a one-sided affair. Take this tweet from S.H.I.E.L.D. executive producer Maurissa Tancharoen, for example, which both encourages viewers to see Cap 2 and appears to tease a potential crossover at the end of tonight's episode:

Of course, she could just be encouraging everyone to stay until the end to get a sneak peak at the April 8 show, which would make sense since we've already confirmed the events of Captain America: The Winter Soldier will weigh heavily on the direction of Agents of S.H.I.E.L.D. going forward. Or perhaps -- like the revelation of Agent May spying on Coulson three weeks ago -- tonight could feature yet another jaw-dropping twist in the final seconds, leaving Marvel fans chomping at the bit to watch both Winter Soldier and next week's episode of Agents of S.H.I.E.L.D.

Lucky for us, ABC was happy to oblige in a press release yesterday, confirming former Heroes star Adrian Pasdar will appear in the April 15 episode as the notorious antagonist and Hulk hunter, Colonel Glenn Talbot. It remains to be seen whether Talbot's introduction will lead to bigger, greener things in the Marvel cinematic universe, but I know I'm not the only one who can't wait to see where Agents of S.H.I.E.L.D. goes from here.

In the end, given both its ratings outperformance and ever-increasing effectiveness as a broader promotion tool, I'm convinced Disney and ABC would be crazy not to renew Agents of S.H.I.E.L.D. for a second season.