IP is basically votes in the UP. It's the total influence points your empire is generating, summed after each turn until the vote comes up. Theoretically, one could buy enough points in influence the UP vote, but the shear number of votes makes it impractical. The difference in value is due to the trading formulas, where at equal diplo levels the AI values it's own stuff much more than it does yours (you selling them the Trade tech would be 7-8 times fewer bc than you buying it from them).

Bottom line, it's not worth trying to buy, and certainly not worth trying to sell.

Maybe they were originally meant to be as mean to influence UP vote... failed spectacularry. The whole diplomacy and UP are pretty much failures in GC2 :/ They work but... Could we please get SMAC diplomacy? Or UN at least?

Sometimes i try to get some IPs when trading but they always cause the trade suggestion to go red...at least if you want more than one point. Hopefully 2.0 will adjust 'em, it is supposed to contain diplo adjusting... BTW when's the post detailing that coming?

They are related, but not the same. Influence points are generated by planets, and affects your borders, planet flipping, etc. The influence points you see in the diplo screen is a running tally of the total number of points of influence you have generated since the last UP vote. Exchanging these points does nothing but transfer tally points from one empire to another. These tally points have no impact on the game except to determine how many votes each empire gets at the next UP meeting.