http://www.swtor.com/user/ce/1ffgaj

The other day, I ran my marauder through Hoth, doing the planetary and Class missions. When I was finished, I had 4 datacrons drop. I didn't do ANY heroics missions. You may have better chances in heriocs, since mobs there have a higher chance to drop loot, but ordinary mobs are dropping them too. As for tracking them, if you look under housing decorations, and set it to available decorations, then look for either Light datacrons, or Darkark datacrons in the list, it will show what you have found already.

...or you can go old school and keep track on a notepad. That's how we did it, back in the day...

I would love to see space combat in the vein of the old X-Wing/TIE Fighter/X-Wing Alliance games, married with the customization of GSF. I doubt it would happen in this game, but perhaps the next one...a fella can dream...

I've been finding them dropping from all sorts of mobs: normal, strong, etc. If I had to guess, I would say that any mob that can drop an ordinary piece of loot, like a gun, weapon, whatever, would have a chance of dropping a datacron instead. Therefore, since tougher enemies have a better chance of dropping loot, those are the ones I'd go after. Just doing my planet and class missions, I find I usually end up with two or three when I'm done.

I believe there is a THORN vendor at the GSI storefront in the Promenade on Nar Shadaa. It's in the upper level, above the imperial class trainers, if I'm remembering correctly.

I"m holding out hope for a mountaintop chalet on Alderaan. So what if it will get blown up in three thousand years?