I don't believe that to be a general problem
as my iPad2 works just as well, via mail, with Yahoo and Comcast as does my ipad.
iPad email Issue with Comcast Internet Service
I have a similar problem. Until several weeks ago, I used the ipad mail app to fetch email accounts with gmail and aol. For some reason now, and only when I am connected to the internet via Comcast, the fetch no longer works. The little wheel simple keeps spinning and spinning. With the ipad mail app I can fetch my gmail and aol mail if I am connected to the internet via my verizon mobile hot spot or via my qwest ISP (which I have at work). It only does not fetch when I am connected to the internet via Comcast service (my home service). Spent hours with Comcast and they are clueless, finally telling me to get a new modem, which I did, but which did not fix the problem. If I use the browser, go to google.com, I can sign in and get my email, but it was so much easier when I simply had to execute the mail app and find all of my email accounts in one place. I use to be able to read and respond to email right from within that one app on my ipad from my living room. I can still access and respond to all my email accounts from that one app, but I have to be at my office, at a public wifi hotspot, or use my mobile hot spot. I think Comcast has "issues" but they aren't willing to look for them.