As someone who studied to take the patent examiner test, several of your presumptions are slightly faulty.
Would posting your idea to public websites, and using the poor man's patent technique ensure that even if someone else patents your idea, you have protection from being sued, and possibly the ability to invalidate their patent?
The certified mail trick doesn't work.
Prior publication could be a bar to issuing a patent, however that doesn't stop the USPTO from issuing patents and letting the courts decide the merits of the case (which appears to be the policy since the mid 90s).
Publishing online won't necessarily help as your website might disappear in the time between when you put it up, and the lawyers start circling. One might take the preventative approach to using DMCA take-down notices to erase your alleged prior publication.
The fee for provisional patents is $110 for "small entities". You may want to contact a patent attorney to see if filing and then abandoning a provisional patent application would meet your requirement to make it so that "patent trolls" can't subsequently patent your invention.
I don't care if someone else implements them, I just don't want to get sued later by some patent troll who patented the idea I had and implemented 5 years ago.
There have been a number of submarine patents, but changes in US law in 1995 mean that the patent runs from the application date, not the date issued. In my opinion, the most notorious one was 4,942,516 which was filed in 1969, and the Patent Office didn't issue the patent until 1988 (they kept sending requests back and forth, which delayed the issuance). Because the application was "in process" this meant that any time someone else tried to file for a similar patent they were autorejected for a patent. This lead everyone in the industry to think that the concept of a single chip microcontroller was unpatentable. Until it was issued in 1988 and the submarine could have sunk the entire electronics industry as single chip microcontrollers are used in almost everything (your microwave, your phone, dozens in your car and so on). Under the new laws, the patent would have expired before it was issued. Under the old laws, the industry had 18 years to develop and mature before the lawyers started looking for 9-digit royalties from semiconductor manufacturers.
That "troll" might have already filed an application for a patent, but it hasn't been issued yet. In this case, you may think you published an article in May 2011, but since the other person filed in 2010, your publication was not prior to their patent application.