Boris, ignore the moaners, they just dont appreciate the same things others do, some love FPS after FPS and some dont, its just personal taste, although i also find it odd & irritating listerning to someone who finds watching one video really boring, then say they've watched a few, and each time insists its crap, but is really intent on doing little more than coming back to kick up a fuss & cause some controversy or something.
Im pretty sure it was first announced at GDC 2007, it certainly wasnt as far back as 2006.
The first time they demonstrated it to the gaming press they did a ~15min demo, the first half explained the basic concept of the game, the creation side of things and how the world & characters interact. Then they moved out of the stageing area of that which brought them to the level which they show in last link you give from GDC2007. They actually did a proper step-by-step walk-through, explaining and showing different aspects rather than rushing through it as you see there.
I cant remember where i got it from, but theres a HD version of this first video to download, i went in search of it a few months back with it being one of the better videos and (to my knowledge) the first showing and it has the full developer commentry and IMO best of all, you've got the press who are there watching who are audiable in the background, lapping it up, laughing and cheering the things being done. How many games can do that??
Since seeing that first video when it came out, i've geniunely believed it'll be the biggest console game of this generation, it'll be the game which takes the industry to the next level with its 'play, create, share' philosophy. There may be games which sell more or people consider better, but in terms of taking that next step into the online world, with user generated content which is easily accessable, i think it'll spark similar movement from other developers.
But i can understand people not being fussed about it, its all about what you want to get out of a game, what you find fun, and how you like spending your time.
Im desperately hoping the EU beta testers get to run ragged in the LBP world sometime before October, but its looking less likely as the days pass by, but it'll be a day 1 purchase for me thats for sure.
I'll have a dig round for the proper GDC07 video, its well worth a watch, especially if you already like the look of it
Might already know, but they used LBP in E3 2008 to make their traditionally boring part of the Sony conference mildly entertaining, having a sackboy go through a level with certain announcements of sale forecasts, minor announcements etc all done with LBP's simple physics triggers and whatnot. Far more interesting than the slideshow presentation MS & Nintendo have given the last 2 years when ive watched their conferences.