I noticed the same thing last year when I was stranded in Barcelona during the Icelandic volcanic eruption. Then, people were looking for ridesharing, free rooms, news, etc. under the hashtag #ashtag. Not as severe as an earthquake, but a similar mechanism blocking twitter's utility.
Then the problem wasn't spam, but #ashtag retweet avalanches from some well-followed celebrities. The most egregious example I remember: this guy Paulo Coelho in Brazil, retweeted through pages and pages of search results (the source: https://twitter.com/#!/paulocoelho/status/12399786645). I'm pretty sure Justin Bieber said something too, so that was it for #ashtag.
This would probably have been easier to deal with than spam, because people weren't actively trying to game them. Twitter just needed to aggregate some information and make it blockable, e.g. "don't show me (re-)tweets with this text anymore". As a sometimes-user, I still don't see a straightforward way to do something like this in the clients I use. So now the spam angle is not a surprise at all.
heh, just realized, in my case, I should have probably taken courses called 'emailing managing directors', 'scheduling meetings in obsolete Lotus Notes versions', 'using that one goofed-up sharepoint where you have to click through six unintuitive links to find the files that anyone actually uses'. (Yeah, I know, my current assignment is pretty lame, sorry-- my snark is directed at it, not you).
Of course, I actually did learn this kind of stuff in college. You do similar stuff in the courses and it applies to the job in unpredictable ways. The point is that you learn to learn, and if you (with the college's help) do it right, you pick up the specific job skills much sooner.
I know (from experience) this can be a painfully hard sell with HR at a lot of places, but saving a few months of learning-curve time for your employer or your clients adds value to the economy, especially in an economy where technology, tasks and jobs change so often.
I think the real danger with a PhD program is that it is so easy to wander into a program, especially once you've gotten a master's degree. It feels like the right move and the next logical step, just like the previous degrees were. It's almost painless to stick around, look into interesting topics, get paid a livable salary, do some research and attend a few conferences. It can even feel like real meaningful work, without the indignity of having to find and start a job.
There is this kind of background worry that the whole thing is getting nowhere productive, or at least not at all where it's supposed to go, but it takes a few years to build up. That ends up blossoming into the regret of three years wasted, instead of a few stressful months (if that) in job limbo.
It's not all bad though. My curious distraction from my 'real work' was learning to program. I ended up with an employable skill that I enjoy using and building on. Still, though, 3 years.
In 2005, I took Motley Fool's advice and sold my Apple stock. Their argument then was that the company had nowhere to go because the Windows PC market was too entrenched, especially with businesses. Maybe they could sell a few more iPods or something, but no real big growth potential. I had gotten about 50% growth to show for my investment, so I cashed out while I was ahead. 30-some bucks a share.
I wish I could find the article, but it's ancient by internet standards, and probably buried by a couple of CMS migrations. My experience is only one data point, but oh wow were they wrong on that one.