Thanks for raising this issue. It's an issue that is quite foremost in the minds of the moderators at the moment.
Firstly, I'd like to point out that user2208439 is by no means the first or the only user to post large numbers of questions in a short period of time, and that I'd like to keep my post to being about the question of serial posting of low quality questions in the general case, rather than commenting on any one particular user.
Secondly, I'd like to split the issue into a couple of sub issues:
- The questions are about the same topic or document.
- What to do about low quality questions
- What to do about new users posting large numbers of questions
1. The questions are about the same topic or from the same document
To my mind, this issue is fairly irrelevant, so long as the user's questions are sufficiently distinct to avoid duplication. I don't care if you're asking for help about the text from 19th century classic fiction or from a technical specification or from anything in between. Whether your question is a good fit for ELL is (to my mind) largely irrelevant of where you got the text from in the first place.
2. What to do about low quality questions
In my opinion, this is an issue that needs to be driven from within the community, and is not something that can (or should) be solved by the executive decree of moderators (particularly unelected moderators). My personal feeling is that moderators should keep as light a touch as possible when it comes to closing questions without having a clear mandate from the community to do so.
What we need is for you, the community, to lead the way on this:
If you see a question that you feel doesn't belong here - flag it, or vote to close. It is easier for a moderator to take action against a user with lots of very negatively scored or closed questions than to take action against a user with lots of medium-scored questions.
If you see a question that does belong here, but is low quality - vote it down and leave a comment. This gives useful feedback to the user, gives them a little kick in the reputation, and allows both the OP and the moderators to see that the community doesn't like the way the OP is asking the question. This also helps make it clear that if and when a moderator does close down the question that he or she does so with the backing of the community, and isn't being heavy-handed.
If you see a question that is borderline off-topic for ELL, or which you feel should be off-topic for ELL, ask a meta-question. A consensus on meta gives your close-votes more weight, and can solve the dispute of whether a borderline question is on, or off-topic for ELL.
3. What to do about new users who post lots of comments
Firstly, there are already some tools in place:
My personal feeling here is that going by the "50 questions in a 30 day period is too high" rule, that "6 questions a day" is probably too high a ceiling for new users, and that perhaps as a community we should be insisting on a lower limit (say 3 a day, and no more than 15 in the first week or something) - but the point is that there is a already a mechanism in place to prevent excessive posting of questions.
In brief - ELL is your community, and it runs on your rules. If you think a user is being abusive, flag it. If you don't like a question - downvote it (or vote to close).