Although Holland America advertises that Internet access is available on board (albeit at the rather expensive rate of $100 / 250 minutes), in reality its Internet access is severely restricted.
Many significant websites are blocked - such as Skype, Vonage and a host of other related sites. Also, while it is possible to retrieve and send email (so long as you are not using a "restricted" site), it is not possible to open attachments such as pdfs and mp3s.
HAL does not have a business center of any kind, as is found in nearly every hotel, to compose letters or to send or receive faxes. Of course, they do not tell you this prior to boarding the ship.
While the Alaska cruise was enjoyable -- good food, excellent service -- HAL's failure to keep up with 21st century business needs to transmit and receive information, should make you inquire beyond the simple corporate statement that "internet service is available on board" when in fact it is severely restricted.