For the technologically astute, Monday morning did not just bring its usual doldrums, because Greg Gillis, the artist behind internet mash-up phenomenon Girl Talk, unceremoniously dropped a new album, titled All Day, on his Illegal Art website, providing music fans with some solace from their working week. This was hardly an under-the-radar event; Illegal Art’s servers crashed due to the crazy amount of downloads. Girl Talk’s popularity, abetted by Gillis’ raucous, sweaty shows, is a surefire sign of the newfound legitimacy of the mash-up genre.

While mash-ups seem to be a pertinent topic, given the new Girl Talk release and the undeniable success of the Cornell Concert Commission’s free Super Mash Bros. headlined “Fall Slope Day” (as it was christened by its more hyperbole-prone attendees), they provide an interesting quandary for this column. There are three obvious topics that over-ambitious writers will likely delve into. First, there’s the question of whether mash-ups constitute a truly creative art form, which is an issue bound to get traditionalists worked up over the lack of musicianship, leading to a pedantic discussion of what really constitutes “originality.”  Second, there’s the idea that mash-ups are a result of our ADD generation that absorbs (excuse the clichéd Twitter reference) its information in 140-character-sized bits. Finally, there’s the controversy regarding the legality of these projects, in which artists give out the music for free so they won’t invoke the wrath of the RIAA, who would force them to pay absurdly large fines if they were making a profit off what is perceived to be the work of others. This leads to a lose-lose situation for the artists, who would end up spending exorbitant amounts of money either way.

But you and I don’t want to hear any of that. There’s plenty of serious discussion out there that skims over the real reason for caring: the music. And while many of you have gotten down and dirty to mash-ups, whether at frat parties or at the aforementioned Super Mash Bros. gig, many, including myself, could hardly tell the difference between one artist’s mixes and another’s. So, as a personal challenge, I’m going to do my best to detail to you, dearest reader, what makes a specific mash-up DJ’s work unique.

The samples an artist uses can very much determine who listens to them. More indie-centric mashers, such as The Hood Internet, are going to attract smaller crowds, since not everyone is going to recognize R. Kelly’s “I’m a Flirt” being sung over the instrumental from Broken Social Scene’s “7/4 Shoreline” (which is, heartbreakingly, converted to 4/4 time). The reason for the success of Girl Talk and Super Mash Bros. is their focus on Top 40 hits. They never discriminate against a genre; if the audience is likely to know it, it’s fair game. This leads to hilarious mixes of Creed, Nelly and Blink-182 (Super Mash Bros.’ “Meet Me At Fantasy Island”). There are differences, though: Girl Talk seems to be more willing to take more obscure risks, delving into 70s AM rock, punk, grunge, indie rock and disco along with the typical hip-hop and dance-pop references. Super Mash Bros.’ samples seem more in line with what a college student would have on their iPod: Lots of rap sprinkled with one-hit-wonders, 90s radio pop and ubiquitous older classics, like the Jackson 5 and Journey.

Another important factor is how songs transition from sample to sample. From the deluge of mash-ups littering the interwebs, one can tell the strong ones from the weak from how seamless they sound. The first goal is to create something that, although birthed from disparate sources, sounds natural but original; there is little room for awkwardness, but there is little room for safety either, because anyone can switch rap vocals, change the tempos and call it a mash-up. The second goal is to ensure that individual tracks, as they develop, don’t devolve into a mere cut-and-paste of a couple of good ideas. As the old cliché goes, the whole must exceed the sum of the parts. Super Mash Bros., while capable of pumping out two- or three-minute bangers, has trouble creating cohesive works. Tracks feel very glitchy, skipping from one (admittedly sweet) idea to another. When tracks don’t make abrupt changes, they use cheap tricks like drum vamps or record scratches to transition. This can lead to some very awkward changes, especially when trading 80's synths for metal guitars in the course of one beat.

While Super Mash Bros. fall victim to the ADD stereotype sometimes unfairly assigned to mash-up artists, Girl Talk, especially on All Day, has found a way to shed it. All Day was initially conceived as a seamless long-player; Gillis split the tracks up the day before the release, for downloading ease more than anything. Samples melt into each other rather than switch suddenly, melding smoothly. Gillis never jerks his audience around, instead opting to allow his seemingly impossible transitions occur gradually. One particularly notable track is “That’s Right,” which subtly moves from Peter Gabriel’s “In Your Eyes” to Beyonce’s “Single Ladies” to Fugazi’s “Waiting Room” in a matter of three minutes, never once feeling inappropriately glued together.

All Day does not represent any sort of mass foray into cohesive, samples-based music — artists such as the Avalanches and DJ Shadow have similarly collage-like effects with more poise and originality — but it does show that mash-ups can overcome their status as mere catalysts for games of “Name That Tune.” Girl Talk’s latest is the type of record that can run your party playlist for you, displeasing no one and fascinating everyone with misplaced sing-alongs that seem wrong but feel oh-so-right.