ADP (www.adp.com) is a company which provides pretty much all of the mentioned services. My employer uses them as the corporate portal for W2s, vacation/sick ti

ADP (www.adp.com) is a company which provides pretty much all of the mentioned services. My employer uses them as the corporate portal for W2s, vacation/sick time and etc. The user experience is terrible and the site won't render right in anything but IE. But these guys thrive because there is no competition. This is obviously not your typical trendy and entertaining niche to be in. It doesn't appeal to most people, like a picture of video sharing service. It's hard to break into the market. Most startups these days are after quick money. They'll roll out, get a decent user-base and sell out the moment they can. Creating a startup in this niche would require a lot ass-busting work and PR to get paying clients.