No in my 1st game my 1st base was near one and just to the north I found another one.

They are much much rarer.

Pretend you've never seen one before ever. Then when you see one, it's cool!

<jedi mind trick>

You've never seen a Lost library

</jedi mind trick>

Playing some turns in a game right now just before going to sleep...

I think they're too rare... in fact I thought they had been taken out because I never saw a single one in playing since Friday.  (I did however see two Temples seeded right next to each other!)

I would say they've become almost worthless, not nearly cool enough to be worth exploring for. Barely worth building in my cities with hundreds of studies.

Making Lost Libraries rarer is fine, but I think we need smaller, less rare versions as well (kind of like the variety of food resources).  That way, we still have tech boosting resources to help balance the equation.

In my current game I've found A single Lost Library, after exploring about half of the map.  It was a ways from home though, and I had to break up a stack of units into blockers to keep Capitar and Tarth from claiming it before my improved Pioneer (designed with a 4 move instead of 2) could get on scene and claim it for the Kingdom.  I was successful and Capitar/Tarth were denied.

I found plenty of Arcane sites though...

That's easy.  If you feel 5 tech points a turn is not effective enough, make it 6-10 tech points, with the rarity Brad alluded to.

Then have something else that produces 5 points.

Personally, even if the 'lesser library' produced 2-3 tech points, I'd still build on it, as long at the build cost wasn't extravagant.  The Study only does one point now, so 2 or more points is an improvement in my book.

In that other Game (Galactic Civilizations II), resources came in a 100%, 300%, and 700% variety.  That didn't stop me from utilizing the +100% sites.  That'd apply in this case as well.

True Gwenio, but you also have to take build time into account.  If I can get a 2 point baby library online in about the same time as a study, and the population cost is appropriate (say 6), then losing 4 tiles isn't that important to me, at least in the early game.  Again, it comes down to how much it'll cost me to build it. 

Plus, if it ever DID become an issue, you could always decomission it later, freeing up your tile count for something else.

AND, if resources didn't count against your tile limit... then they become even MORE attractive.

And if there was a 'baby library' upgrade via tech research, that could be used to make them more useful later.

I've yet to max out my city tiles... usually I've wrapped up the game before that becomes an issue.  That may change in 1.1 though...

surely a lost library takes no tiles not four.

I think this is a good idea. I'd go further and have it unlock technology that is only accessible by controlling a lost library.  This would be somewhat similar to what the MOO series did when you took out the guardian and gained control of the Orion system. 

There have never been "lost libraries" in Elemental. I think you're thinking of a different game...

Lost what???? Is this one of those North America only things? My mind draws a blank on this   

I sort of cringe at the idea that the majority of research now comes from overloading your cities with Archivists and such. I've run into the issue already in 1.09n where research is the only thing worth building in my cities. Which has undercut the value of specialization. Added to the fact there's no scaling or diminishing returns on city-built research....yeah. Lost library is a perk, but it's going to be amount to drop of water in the bucket in a mature game.