No idea. Although I'm not your target audience, the site seems to me to be perfectly respectable and useful.

I very much doubt it was any of the factors you mention. It is likely that as a new user with low karma it takes fewer "flag" clicks to kill your item, but I don't see why it should've attracted any flags at all.

It does, however, read a lot like an advertisement, and perhaps people thought it was really spam, a point of view bolstered somewhat by the new user/low karma issue.

Try again, only this time perhaps say what you want from HN readers. Ask for reactions and advice, and see if it gets flagged dead again. It may have just been unfortunate timing. My recent item asking for article suggestions in sinking largely without any reaction - http://news.ycombinator.com/item?id=1540610 - but I'll just shrug and move on.