♦  You’re on the live stream for Occupy Wall Street streaming out to about 2000 people
• The noun, “live stream,” and the verb “ stream” (“live stream”) refer to the process of broadcasting an event on the web as it is happening, as opposed to recording a video, uploading it to a website, and storing it there. The video on which this exercise is based, “Occupy the DOE,” was originally streamed on the “Live Stream” site on October 25, 2011, and has been archived there since. (According to information published on the Live Stream site, anyone may establish a “channel” there and broadcast free of charge. Ten gigabytes of storage are also provided free. Fees are charged for ad-free channels, higher quality video, and extra storage space.) (There is some general information about live streaming in the Wikipedia article, “Streaming Media.”)
♦  What is your background?
• A person’s background is what they have done in the past especially as it is relevant to something they are doing at a particular moment (e.g. applying for a job, running for political office, speaking in public). Here, Michelle could answer by giving information about her job, her education, where she lives or where she grew up, how she got involved with the “Occupy Wall Street” or the “Occupy the DOE” groups etc.
♦  it seems like it set a ...It got them a lot of momentum going.
• to “set a precedent” is to do something for the first time, especially in a legal or political context which will, because it has been done once, be done repeatedly in the future. The phrase would not be quite correct here and so Marcelle is right to stop herself and to use the word “momentum” instead. Something — a political movement for example — has “momentum” if, because it has been growing and moving forward strongly, it will probably continue to grow and move forward.
♦  I knew people in NYCORE (which is the The New York Collective of Radical Educators)
•According to the mission statement on its website, the mission of the New York Collective of Radical Educators is to fight for “social justice in our school system and society at large, by organizing and mobilizing teachers, developing curriculum, and working with community, parent, and student organizations.”
♦  I started going to grade-ins
•A “grade-in” is a protest in which teachers draw attention to their grievances (i.e. their complaints by doing their part of their work — grading (i.e. marking) student assignments in a public place. The phrase “grade-in” along with similar phrases like “die-in,” “teach-in” and “work-in” are all related to the “sit-in” a form of protest that was much used during the American civil rights movement in the 1960s. (See the Wikipedia article on sit-ins (which contains links to articles on the other similarly named types of protest and also to the article on “sit-down strikes” which were a precursor of the sit-ins of the 1960s.)
♦  Well, to be honest
• According to A Comprehensive Grammar of Contemporary English, §8.127, p 620, the phrase “to be honest” is a “content disjunct, type B.” Disjuncts of this type express the speaker’s opinion of what he or she is saying. (Most commonly disjuncts of this sort are realized by an adverb (for example, rightly, foolishly, amazingly) but, as here, prepositional phrases and clauses can also be used in this way, for example, to my regret, to our surprise, which is to be expected. What Marcelle is saying here could be paraphrased as follows: “But I don’t want to give the wrong impression by suggesting that we were really grading all the time at the grade-ins. In fact, we spent a lot of time organizing today’s meeting. ”