What is a Mesa Boogie Rectifier amp and why is so popular 

Mesa Boogie Rectifiers are iconic amplifiers and I would say the most known of the brand along with the Mark series. They were released in 1992 and got their name due to its rectifier circuit (that ALL amplifiers have btw) and can be done using a tube rectifier or a diode rectifier.
There are bunch of different models and revisions, some of them have only offer diode rectification, other offer switching for tube or diode rectification.
Depending on the wattage, single rectifiers are 50 watt, dual rectifiers are 100 watt and triple rectifiers are 150 watt. They have different options depending on the model like multiwatt switches of each channel, some of them have 2 channels, others 3 Channels (indiferently if they are dual o triple rectifiers).
They also may have reverb or even tremolo (rectoverb or tremoverb). Apparently, the most sought after models are the Rev G and Rev F ones (as far as I know). After the release, Mesa kept doing small changes in the circuit so they sound slightly different. Comparing the serial number of the amp with the Mesa records is the only way to know which revision a Rectifier is.
The most advanced models that have even more bells and whistles are the Roadster and the Roadking with 4 channels, 12 modes, totally over the top LOL.
In this video I would cover why I think it became so popular, the main characteristic of the sound and the bands that used it:
Creed/Alter Bridge, Colective Soul, Tool, Soundgarden, Korn, Limp Bizkit, Blink, 182, Foo Fighters, Linkin Park, you name it!!
Once you hear about this you will also understand the issues that it has and why using a tube screamer or any overdrive / boost pedal helps to improve the sound of it