The Internet has really screwed up the notion of permanence.
I have seen some rather insightful observations made lately on how today's kids are going to grow up able to retrieve much of what they said when they were younger. This is, of course, thanks to the fact that they're stuffing nearly every casually uttered word into the maw of Facebook, the company least likely to even consider deleting a word of it.
Of course, this is nothing new; only the scale and commitment is novel. Words given over to the Internet have always been subject to immortality, and sure enough, a number of the more embarrassing conversations I've had in public fora are easily retrievable, thanks to mailing list archives and Google's Usenet indexing. Even the slightly more cozy conversations had on IRC can be found in personal logs, kept (hopefully!) not for blackmail or other nefarious purposes, but simply because they were so easy to record and keep and sometimes proved useful for recall.
Contrast this with casual, verbal conversation. Unless someone is pointing a sensitive microphone in your direction—which I believe is still considered a major affront, though you may want to check back in a few years to see if culture has changed in this regard—you are able to speak in relative freedom, with the only records being the memories of those you are speaking with and maybe anyone who has chanced to overhear. As we move conversations of this nature increasingly to the network, where recording is a given—be it for public consumption or as grist for the marketeer's (or worse) mill—we can no longer rely on this comfort (or, at least, we should not. Going by posts I've seen made on social networks, it seems many have subconsciously convinced themselves they are only speaking to their select small circle of friends who reply, and are blissfully unaware of the fact that their words are copied hundreds more times to people who they would never dare speak them to face-to-face.)
But pushing unwanted permanence on our casual conversations is not the only problem being networked as we are has created. There are, of course, times we want to be on the record, times we want to have everyone hear what we have to say. In times past, we may have sought an audience, counting on someone to record and disseminate what we say. Or, we may have chosen to put our words to print, counting on the natural tendency of the physical, printed word to insure they are not forgotten.
Fast-forward to today and another troubling trend emerges: in our quest to achieve ease of dissemination, we have turned to a myriad organizations who will publish those thoughts for us—but in their own domains, where their continued existence is dependent on said organizations' profits, business model, level of comfort with what you're saying, and even just the winds of technological change. Of course, if you haven't signed your rights away, you can take your words with you if the place you are publishing them decides it's in their interest to stop—provided you have either enough notice or backups—but the external references to your work are then irretrievably lost, all now pointing to nowhere useful.
What irony! Those channels which we have traditionally counted on being fleeting and casual must now be used carefully, since they are now neither; and when we do wish to be put on the record, our words are only so as long as a third party considers it to their benefit to keep them so. But it need not be this way. We already have the technology to turn this tide. We can leverage public-key cryptography to keep our casual conversations casual. We can choose to maintain control of what we say publicly, rather than handing it over to a third party with their own interests.
Unfortunately, changing this M.O. is going to mean that the “free” (“If you are not paying for it, you're not the customer; you're the product being sold.” But that's for another essay) rides many enjoy today will be a thing of the past, and development investments will have to be made that investors will shy away from, because the potential ROI in controlling swathes of the network won't be there. Readjusting the permanence of speech in the age of the Internet will take effort, but I think it's something we need to do.