On the forums most people include the CiviCRM version and the CMS and version in their forum profile.
I find this very useful even though people sometimes forget to update it and it is of limited value for consultants who work with many versions (although those people are usually savvy enough to include that information in the actual post).
Here that information is often missing from a question.
Is it important to have and if so how/where do we tell people we need that information to be able to provide a relevant answer. Should it be part of https://civicrm.stackexchange.com/tour?
Should we have a standard comment asking for the information that is routinely added to questions that don't include those details.
Should we have tags for the different versions of CiviCRM? (perhaps starting with 4.2 or 4.4) Would this help people find Q and As that are relevant to them?
If we don't think it is important should we always answer based on the latest version of CiviCRM (ie now we answer for what applies in V4.6)?