Already couple of years ago, I found that Yahoo services were providing most, if not all services that a small company need to run their business.
Obviously, more and more companies are providing IT tools and services online on the Internet. Of course, most of them in messaging and collaboration services, but the trend is there and Enterprise services for Finance, Supply Chain, HR, etc might come in the future... it will be all about risks vs benefits...
I like particularly Web Office for the "intranet" solution, which incorporate collaboration, documents management, web meeting and email all in one service, quite impressive.
Take also in consideration Groove, the peer to peer solution, very nice instant collaboration. Groove had been founded by Ray Ozzie the inventor of Lotus Notes and had been acquired by Microsoft earlier this year. Knowing that Ray Ozzie will become Chief Software Architect after Bill Gates next year, we should definitively keep an eye on what he is doing!