I've been semi-following a discussion on if smart people are getting smarter on an online forum I frequent, and too much popped into my head to allow myself to post it out there with a good conscience. I'm gonna ramble about intelligence...
I haven't noticed if someone has brought the concept of collective intelligence and it's effect on how we perceive information up yet, so if I am repeating something someone has already mentioned, please forgive me for it.
One thing that can seemingly affect the increase in IQ for mankind are the new means with which the collective knowledge of a society is stored and it's accessibility. Earlier libraries were owned by the privileged elite with better educational opportunities, these days anyone with a head on their shoulders and the desire to learn can get their hands on books, magazines, television, and internet to mention the common ones, whether it be library or bookstore.
The kinds of intelligence are varying. Based on a researcher who spoke a few years back at a MENSA meeting, they actually claim, that a person's intelligence starts off as active, and with age, as one studies and learns more, becomes a crystallised, solid specialised knowledge of usually a relatively narrow subject matter, which will decrease the portion of brain capacity dedicated to learning. It's not as simple as that, but it's the easiest way to explain it briefly...
When a specialist in his or her respective branch is asked to solve a problem, he has the brain crunching power of one individual, but the solid knowledge of often decades of study into the field. However the same results can also be attained by a team of students barely familiar with the subject when starting.
Why? Because they can split up and research the amount of literature one person can research several times over in the same time.
Because they can use modern communications tools to compile that information, and they can brief each other on their progress and act as a form of a control group for each other, to see they really are making progress, and bounce ideas off of each other.
That's one of the main points of a two or so hour lecture, so please excuse the briefness of it. The lecturer is not a big fan of societies like MENSA, which only accepts members who score in the top percentiles of the population in standardised IQ tests. Based on my observations their member forum's activity, they can still act petty and argumentative
(with the added element of being too focused on whatever happens to be on their minds at any given moment for them to notice no-one's interested in the molecular structure of some or other neurotransmitter miracledrug and whatnot...), though :/
I have to agree on the fact that the intelligent individuals seem to be "smarter" than the previous generation, but on the other hand, information is easily available, and not all educational facilities have the time or resources to actually bother cross-referencing essays and other academic student work with existing material for outright verbatim plagiarism to just lazy stupid copying of unverified data.
Television is a massive distraction. I have two teenage brothers, who haven't really ever bothered to read a book for their own amusement. It's always been schoolwork, and even then grudgingly, because I didn't give them the synopsis in the name of their own good. Both have a diagnosis of dyslexia, but they have never bothered reading or writing for fun. My good friend and classmate was severely dyslexic and made it through school with better grades than I did and read as much as or even more than I did. Sometimes it feels as if the diagnoses are a little too easily given these days, when the reasons are as simple as laziness and being too easily distracted by television, computers and the games console(s)...
...which can lead to others labelling people as "stupid". The 15 year old brother is highly intelligent and could grasp the basic concepts of some college level math at age seven (he "helped" me with my homework because he thought it was fun), but didn't like reading books. He also hasn't lost a game of chess to an adult since he was nine.
His high mathematical and logical IQ still doesn't prevent him from thinking it's a good idea to fire an airsoft gun at his Marines Reserve SWAT sister, or that it'd actually be a good thing to think before acting. Intelligent, but definitely thick when it comes to self-preservation instinct

The biggest changes have perhaps been in the availability of information, and how some individuals handle it. The old way of teaching, that is still prevalent in many places, that is very much based on the notion that the more one memorises by heart, the more they know the subject to me seems to be almost alien.
In my equivalent of senior high, we for example had the antique Greek method of dialogue (originally meaning conversation,
discussion derives from Latin and can refer to a more argumentative conversation and we all probably know what
lecture means...) between us students and the teacher, who was also the headmaster, sitting by a round table in a library in stead of a classroom. Discussing what we knew, volunteering to research new information ourselves, having the whole problem based approach to assignments and being required to bother with research by ourselves and having to list our literary (we didn't hang out online much back then) sources led us to approaching problems outside school in a similar fashion.
In work life you aren't handed a book and being told to memorise it by heart every day or week or month. You are handed a problem and you need to solve it. The easiest way isn't to memorise your 60GB worth of literature that you've got stacked up in a library, but to figure out a system for you to easily have access to that information when you need it, and how to get it fast when it's needed. You rarely have exams in your work life where you can't have any material with you to writing your test, if someone calls you with a problem, you're highly likely to look the answer up for them from a folder, book, an email or a website.
That ability to have a form of a flexible intelligence where you in stead of memorising everything memorise where you have stored the required information and how to access it efficiently is to me a form of honed intelligence as well, that few mention and even fewer take advantage of.