A plural refers to the "s". As allrisks rather than allrisk.
What I find interesting is that in this context I think the "s" is better. This would be an insurance site and deal with risks. These risks are not singular but a variety of different risks and hence are plural.
In general yes a plural is a not so good but not in this case. I think it is better and more valuable for having the "s".
A good name to list and link different insurance sites through. All these sites I think pay good click through so it should be a good earner.
I'll stick my neck out on this one a bit. Put the links in place and I think it could be worth over $1,000. And the good thing is that your only risk should be a little of your time.