It's been a long but successful road for Joss Whedon's Dr. Horrible's Sing-Along Blog. The Buffy the Vampire Slayer creator came up with three-part musical 2008 during the WGA strike, penning the musical with brothers Zack and Jed Whedon as well as Jed's wife, Maurissa Tancharoen (who co-stars) as a way to go outside the studio system and explore the web series phenomenon.

The result can only be described as an Internet phenomenon. Overwhelming demand to stream and download the first 14-minute act crashed the servers. Sales lit up on iTunes. Lines to watch the 45-minute screening at Comic-Con snaked all over the San Diego Convention Center, prompting overflow rooms to fulfill the overwhelming demand. A DVD release, comic book line and soundtrack resulted. And now the story of Dr. Horrible, a villain with the heart of gold (played by How I Met Your Mother's Neil Patrick Harris) and a dim-witted (but handsome!) hero known as Captain Hammer (Castle's Nathan Fillion) going head to head over the affections of a sweet and idealistic woman named Penny (The Guild's Felicia Day) is coming full circle: airing on the CW.

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"It's a big victory as far as mainstream Hollywood acknowledgement of web series as a legitimate format," web series creator/producer/star Day tells The Hollywood Reporter. "I really hope that it's not just a singular thing anymore, that it becomes a trend. That's my biggest hope."

And Day should know: she not only starred in the series but it was her work on The Guild that inspired Joss Whedon to explore opportunities that existed outside of the traditional Hollywood studio system, where creators could have complete control over their content from budget to casting and everything in between.

THR caught up with Day ahead of Dr. Horrible's broadcast premiere to discuss what it means for web series, buzz about the rumored sequel and get the latest on her own YouTube channel, Geek & Sundry.

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The Hollywood Reporter: Was it always the end game for Dr. Horrible to air on broadcast TV?

Felicia Day: I can't speak for Joss and the creators but I know that what Dr. Horrible became over four years ago is what it meant to be -- it was meant to be an Internet phenomenon. Even to this day, there is not anything that's been released on the Internet to equal it as far as reach and revolutionizing and showing people what digital could be.

How did Dr. Horrible set the stage for what other creators are doing now online? We've seen CSI's Anthony Zuiker and Touch's Tim Kring both take on series.

It's definitely was years before its time. It set an idea for what digital could be so early on that it started a wave of content that then faded a little bit in 2009 and 2010 because everyone expected that to be the standard of the space and when that reached its apex there was a lull in web video. This year is the year that that potential is being shown. Not only do you have independent creators creating things of extremely high quality that are getting millions of views on the web but you also have a lot of experienced Hollywood producers and creators entering the space because they see the creative freedom, all the different distribution points that are possible and they see the reach you can get with global audience. If anything, Dr. Horrible was extra before its time in showing what the potential was.

How will airing on the CW help with the rumored sequel?

(Laughs) I'm just a passive participant in what ever sequel plans they have. I've heard many talks about what the follow-up could be and the plans for that. I know it's probably on the forefront of the Whedon camp's mind, but I think they're busy with a lot of other things but it seems to be a lot more positive nowadays. Hopefully a whole new audience finds Dr. Horrible as something new is going to be really motivating and exciting to see other people discover it for the first time.

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Should the airing prove successful for the CW, do you think Dr. Horrible could continue on as a series for TV?

I think anything is possible. That's the great thing about incubating something on the web: you have the potential to go to other platforms. Every single platform has a different audience that you find. You could scale upward in a way that is not as big a commitment. I think it's a fantastic opportunity because the world building is so strong, and the characters are so strong that Dr. Horrible could go anywhere, on any platform and I'm excited to see it take another step.

Do you consider landing a broadcast home the crowning achievement of the series?

I think the crowning achievement was creating a grassroots phenomenon around the show. Yes, it's an amazing event to be able to be seen by millions of people on television but I think the goal with Dr. Horrible was to show this other path of creative freedom. Walking into Comic-Con and filling a 5,000-seat hall with a web project that was made so low-budget was an immense victory. It is going to be cool to watch it on TV and hopefully we'll have some kind of get-together. I think I need to send an email! (Laughs.)

How big of a victory is this for series made exclusively for the web?

It's a huge leap for web series. Just acknowledging that something made outside the system can be integrated into the system in a way to create broader kinds of entertainment. The development system, there's lots of awesome shows out there but the possibility of creating something completely independently and have it be aired on traditional airwaves hopefully will inspire other people to do the same thing. Then a more diverse set of stories might able to be told.

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Given the success you've had with Geek & Sundry and The Guild, would you be interested in taking Dr. Horrible to the CW as a potential weekly series?

I can't speak for that. I'm just a very lucky actor to be a part of that. As web creator, it's a huge step for the series and for all web series creators. I'm thrilled to see it leap to TV.

You're launching a new lineup of Geek & Sundry offerings. What's the next step for your YouTube channel?

We're halfway through our year of content and we've done amazingly well. We've created a huge community around the channel. We had an off-site Comic-Con event that was packed the whole time. My goal in creating Geek & Sundry was to create a community based around web video and we've accomplished that, especially on our budget. We're halfway through and we have The Guild season six coming, which is fantastic. We're leaping platforms from Microsoft back to YouTube, which is a testament to my keeping the IP of the show that I can move it from one place to another. We're getting it in a more interactive and innovative way with extra content and little Easter eggs here and there to take advantage of the flexibility of the more social platform. We also have a few other scripted comedy series coming out. We're looking at what's succeeding and trying to invest and put more content into those verticals. Cross fingers we get another season/year of content picked up, we have have plans in motions to produce new shows, take pitches and develop other properties that with Dr. Horrible in mind, platforming it to TV is definitely not out of our question in a long-term way.

Have you had those conversations with networks yet?

It's still early. We're incubating everything and trying to make hub of our YouTube channel our central focus. The Guild has been on every single platform; it's become the one web series besides Dr. Horrible that fills up multiple thousand people rooms at Comic-Con. My goal with every show we put on Geek & Sundry is to make it that big of a success, not just within the video but within fandom itself. We're excited about expanding our eye after we get everything developed. We're considering it more of a start-up company. Six months in, we've met a lot of our benchmarks and hope to grow from here.

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With The Guild, is there space for that as a weekly series on TV? You certainly have the content for it.

We've done six seasons of the show on the web and as a creator myself I'm eager to explore different formats. I'd be open to it, definitely.

Have you been approached by anyone about that yet?

Not specifically. I've been a bit busy producing seven shows at once, which has been a learning curve for me! As we emerge from Guild season 6 rollout, we'll be looking at all possibilities.

Dr. Horrible airs Tuesday at 9 p.m. on the CW. Watch a promo, below. Day's The Guild premiered its sixth season on YouTube last week. Watch the first episode, below.