I believe number 6 is the least helpful because it has nothing to do with the post and it uses slang. The next least helpful is number 1 because they use quite a lot of slang and it does not have any helpful information. 4 is next because is has nothing to do with the subject and it does not have correct spelling. 8 is also not very helpful because it does not have useful information. 7 is also not helpful because it does not show good information and what you like about it. 2 is helpful because it shows what you like about and useful information. 3 is also very helpful because it shows connections they have with the book and its shows you like it.  I believe 5 is very useful because its shows your opinion very well and what you like about it.