Cisco has discontinued its hosted email solution, which never really got off the ground in the first place.
Anyone else ever heard of Cisco Mail? If you have you're most likely one of the few "trial" participants Cisco hosted on the service. I'm unsure who thought this was a good idea at Cisco, seeing as email hosting has been a commodity now for 5+ years.
The only interesting feature Cisco brought to the table was its IronPort spam protection, which is itself Software as a Service (Saas) and a well respected one at that. For the price of Cisco Mail ($5/month/user) though, companies could sign up with Google Apps for Business, which has its own excellent spam mitigation system in Postini.
You can read Cisco's explanation on their collaboration blog.