Firstly investigate if there is anything trademarked or patentable (I doubt the latter due to court cases like Alice killing off a huge amount of business process patents).

Just don't do anything completely stupid like steal any copy from the site and repost it.

The fact is that there is no end to situations similar to yours. Just because someone is there first, doesn't mean you can't do the same thing - even in most cases exactly the same thing.

In fact, you're in a better position bearing no legacy and not having to pay the heavy price of educating the market on the value of the offering. You just have to innovate within it, or market better, or expand the market.