In theory it is possible that requests can be made via sites such as Facebook and Twitter, but to be valid they still have to comply with section 8 of the FOI Act, which requires that requests state the name and address of the applicant and an address for correspondence as well, of course, as describing the information requested.
Requests which are anonymous or which use pseudonyms will not be valid. This is less likely to be an issue with Facebook (Facebook asks users to provide their real name), but may cause problems with Twitter. Although it may be possible to find out the real name of the applicant through a Twitter user's linked profile, the Commissioner takes the view that, for the request to be valid, the name of the requester must be evident from the tweet itself.
As mentioned above, you must also include an address for correspondence. Given the restrictions on responding (see below), it is preferable if the request contains an email or postal address where a response may be sent.
Where your request does not specify the name of the applicant or an address for correspondence, public authorities should, in line with their duty to provide advice and assistance under section 15 of the FOI Act, tell you what you have to do to make the request valid and how best to use your information rights. Often, the easiest option will be for the authority to ask you to make a new request via email or suggest they use www.whatdotheyknow.com. However, if the information can easily be provided, public authorities may instead choose just to disclose the information, while making you aware that the request is in fact invalid.
Public authorities are likely to face difficulties replying to requests made via Facebook or Twitter, particularly if they are refusing to disclose information (given the need to issue a notice complying with section 16 of the FOI Act) or are disclosing large amount of information. (As is well known, Twitter only allows messages of up to 280 characters.) In order to comply with the FOI Act, public authorities must "give" applicants information (see section 1(1)) or "give" a notice (see e.g. section 16(1)) explaining why the information is not being provided. It is not yet clear whether providing applicants with a link where they can access the information or read the notice is sufficient to comply with this duty, although applicants are perhaps unlikely to complain if information is provided, or a notice is given, in this way. Again, the best solution may be for the authority to ask you to provide an email or postal address to allow the authority to "give" a response or suggest they use www.whatdotheyknow.com.
The Commissioner has not yet received any applications for a decision following on from a request made via Facebook or Twitter and this is new and untested area. Decisions as to whether requests (and subsequent applications) are valid will be made on a case by case basis and this guidance will be updated to reflect any decisions made.
Public authorities should also be aware that requests for environmental information made under the Environmental Information (Scotland) Regulations 2004 (the EIRs) may, given that there is no express requirement to provide an address for correspondence, be more likely to be valid if made via Facebook or Twitter than requests under the FOI Act.
Finally, authorities need to remember that they are under a duty to provide advice and assistance to you. So, if you are trying to make a request through Facebook or Twitter, the authority should respond.