I didn't get 'smarter' per se, but I got much better with interpersonal communication and the start of this trend coincides with getting in touch with LW (It also overlaps the breakup with my ex-wife but I think I can rule out a causal connection there).
Actually a lot of specific changes in my behavior can be traced back to specific advice from LW. I cannot rule out that by natural development I might have acquired these from other sources but I think the sheer amount of changes speaks a clear language.
I considered a write-up of this development from my Rationality Diary entries and such (I think Brienne mentioned somewhere that we need more success stories) but my low success with more elaborate posts here has discouraged me from that.
I feel I've learned a lot about problem solving from less wrong (and HPMOR in particular). be concrete, hold off on proposing solutions, et cetera. The effect*, unfortunately, doesn't seem to be as much as I had hoped.
Small increases in intelligence are extremely general and even recursive, so it feels worth the effort. But, I found alternatives much more effective (though still modest) then studying/discussing/applying the sequences. like meditation or smart drugs.
I'm interested in other lesswrongers experiences in cognitive enhancement.
* by "smarter" I mean "better at problem solving", where examples of "problems" are writing a program, finding the right thing to say to resolve interpersonal conflict, memorizing some random fact quickly and then recalling it quickly/vividly. let me know if you want further clarification.