The genre and style of public service announcements hasn’t changed considerably over time. The way they existed in the 30s and 40s is very different from the way they are now, however their intent has always been consistent, as they serve a very specific social purpose. Originally PSAs existed as extended short films with the purpose of bringing about social awareness of a cause. They were heavily focused on concerns with the war effort, and were almost a type of propaganda. There are also several different approaches in delivering PSAs, as many have played all around on the spectrum between comedy and tragedy, so as of recent there have been very few revolutionary concepts introduced into PSA production.
Despite this there have been two relatively large changes in PSAs which have helped to influence their style. First the length has changed drastically from the 40s and 50s. Back then PSAs were more like short films which took up a portion of broadcasting airtime. Now they almost exclusively exist as commercials, with story lines confined to a 30 second to minute long time span. This has forced PSAs into having to deliver an entire story arc with an effective message in an incredibly short amount of time. Another development that has spurred within recent years is the use of sincerity and graphic depictions. The worst PSAs are those which come off as melodramatic, and many “serious” PSAs have ended up being this way. Good examples of melodramatic PSAs would be Brain on Heroin (http://www.youtube.com/watch?v=PawmEoFy_2o). The message falls flat in these commercials and become humorous, which defeats the purpose of the advertisement. Recently the Montana Methamphetamine Project hired Darren Aronofsky to create a series of PSAs(The most powerful in my opinion are the ones titled Friends:http://www.youtube.com/watch?v=GDUoXp4cB_c Mother: http://www.youtube.com/watch?v=Irvl4pLA9A0 and Desperate:http://www.youtube.com/watch?v=uq6Vg8Hm5VA) These 30 second commercials are intense and genuinely dramatic, and are in my opinion some of the best PSAs created.
I think that PSAs are still very relevant within popular culture, as they are often recreated, referenced and parodied in many different formats. They also are able to inform people of issues and concerns they might not be aware of, thus they still having a valid purpose. I am most interested in seeing PSAs with improved writing quality (like the Montana Meth Project) as they are jarring and well done pieces of short film. Humorous PSAs have already been well established and I think are a lot easier to pull off, which makes the possibility of good dramatic PSAs extremely appealing to me. PSAs are also developing a presence of the internet and some informal viral PSAs that were created have been very effective. This one (http://www.youtube.com/watch?v=d-XHPHRlWZk) plays off of the make-up tutorial genre to deliver a powerful message about domestic violence. Videos like these are able to reach an entirely different audience, and are a great format for PSAs to develop.
In terms of where PSAs can go from here, I think it would be interesting to see PSAs made for issues beyond what they are made for now. PSAs often take on obvious evils like drug use, unsafe driving practices and other miscellaneous hazards. However, I would like to see some PSAs informing viewers on structural violence or other greater aspects of our society which have birthed a plethora of problems. The format of the PSA has such a large potential for bringing about change, yet I don’t think those capabilities have quite been realized yet.