What year did the minicon "micro BrickCon" first appear at "BrickCon"?
In the blog of Tom Aplhin he mentions regarding Microscale


  Steve Oakes, a long-time LEGO builder in Seattle area started a tradition 4 years ago to re-create the BrickCon Public Convention at a smaller scale. His display is called “Micro BrickCon”


(Edit: The conversation between Tom and myself was in a loud room with lots of activity. He is correct about everything except the year.)

After building and displaying an 8.5 foot stern paddle wheel ferry boat at BrickCon 2011, I decided it would be easier to build smaller MOCs. I kicked the idea around for a while, and then came up with the concept of making a micro-con. Mariann Ansunuma, former miniland builder at Legoland, and current maker of awesome microscale Lego jewelry, liked the idea and took me under her wing. I built 2 tables, displays and minilanders to display at BrickCon 2012. I was very pleased when Mariann brought along a third table, displays, and minilanders to add to mine.

After the initial Micro BrickCon MOC was displayed, Mariann, who travels to various cons with her vendor booth, took her portion of the MOC and introduced it to cons across America. It has since become a theme featured across N. America, Canada, Germany, and Australia. 

In 2012, the MOC was just a MOC. However, micro BrickCon was so well received, in 2013 it became and remains it's own theme. In 2012 7 builders contributed one thing or another to make the MOC better. In 2013 and 2014, 22 builders contributed, and this year, 2015, 29 builders joined in. 
                                                                 -Major Stackings