The DOL issued a Safe Harbor for electronic delivery

The DOL has set forth requirements that would provide a Safe Harbor for the disclosure obligations under Title I of ERISA utilizing electronic delivery at the workplace The main DOL requirements for Safe Harbor delivery at the workplace are listed below, but the guiding principle is " the plan administrator shall use measures reasonably calculated to ensure actual receipt of the material by plan participants, beneficiaries and other specified individuals " (DOL regulation, Part 2520 Amended, paragraph 2520.104b-1(b)).

The electronic delivery method must be devised to reasonably ensure the actual receipt of the transmitted information (i.e., use of return-receipt or notice of non-delivery electronic mail features; periodic reviews or surveys to confirm receipt).
The electronic delivery must protect the confidentiality of the personal information relating to the individual's accounts and benefits by including measures that prevent unauthorized receipt or access.
The electronically delivered information is both complete as to the content prescribed and consistent with the format and style requirements for the particular document/notice/form.

At the time a document is furnished electronically the recipient must receive notice (either electronic or non-electronic) of the significance of the information provided (unless it is reasonably evident from the communication itself) and must be informed of the right to request and receive a paper version.

The Safe Harbor for electronic delivery in the workplace only applies to individuals who have the ability to effectively access documents in electronic form at any location they are reasonably expected to perform their duties as an employee and who have access to the employer's or plan sponsor's electronic information system as an integral part of their duties.

In short, availability of a kiosk will not satisfy the requirement.

Putting information on a CD is the least stringent method of electronic communication, particularly for expansive information like prospectuses. With appropriate disclaimer attached to the CD notifying the participant of the ability to request paper copies (among other things), distribution by this method qualifies for the Safe Harbor .