I’ve written before about the difference between the pop charts and the Hot 100. The Hot 100 is the definitive record for the top singles at any given time (and is a composite of airplay, sales and online streaming), whereas the pop charts only track radio airplay.

I don’t refer to a song as a true number one song unless it’s at the top of the Hot 100 because there are so many different charts and the ranking of number one becomes a little less meaningful when the criteria is dilluted. (Same goes for albums and the Top 200.) Sure, some great songs (“Toxic” is the first to come to mind) were big hits but never hit number one on the Hot 100 (but did on the pop chart) while lessers, like Owl City’s “Fireflies” topped the Hot 100.

The reason I bring this up, though, is because it was announced this week that Lady Gaga became the first artist to have her first five singles hit number one. Her first two, “Just Dance” and “Poker Face” both did hit number one on the Hot 100 and the next three did land in the top 10 (“Bad Romance” may still reach the penthouse when Ke$ha’s momentum for “Tik Tok” slows down), but this first five singles record is less impressive when you consider that the pop chart (or Top 40 Mainstream) has been tabulated since October of 1992.

On another note, The Avett Brothers have the number one album on the folk charts now and it was the first-ever non-holiday album to top the charts, but that is because the chart is barely a month old. Not to discount The Avett Brothers at all, but their most recent album is currently #130 on the Top 200 and number one on the folk charts, which shows the limited market share the genre holds. (They did peak at #16 for their latest album, I and Love and You, but that was in October, before the folk chart even existed.)

While Lady Gaga did technically take her first five singles to number one, and that is certainly impressive, it would just be more impressive it it wasn’t such a technicality.

When compiling album sales charts, Billboard counts double albums as two units. For example, chart expert (and friend to this blog) Chris Molanphy pointed out that when Pink Floyd’s The Wall has sales of more than 23 million albums, there are actually only 11.5 million people who own a copy of it. It’s still a lot of people that own it but more people actually own Dark Side of the Moon (15 million+) than The Wall.

What is even more puzzling, though, is this explanation from Billboard for the number five and six albums this week on the Top 200 albums chart (which I think will appear on Billboard.com tomorrow):

Lady Gaga’s new eight-song quasi-EP “The Fame Monster” bows at No. 5 with 174,000 while her first album “The Fame” rises from No. 34 to No. 6 (151,000; up 429%). The latter “Fame’s” total jumps this week because it combines sales of her debut set in addition to a two-disc deluxe “The Fame” package that contains both “The Fame” and the new “Monster” disc.

Lady Gaga just re-released her album The Fame bundled with a bonus, eight-song EP and the whole thing is called The Fame Monster. You can, however, buy the EP separately. If I’m reading this correctly, Billboard is combining sales of The Fame Monster so that people who bought the deluxe edition with both the proper album (released in the summer of 2008, by the way) and the bonus EP each count as one unit. The expectation from Billboard before the week began was that Lady Gaga would sell around 180,000 units this week, so she was a little below expectations, she didn’t blow it out of the water by having 325,000 people bring home Lady Gaga albums last week.