You can trade blocks of IP for cash tech or trade goods. I used to trade for IP in GCI but it has never been my favorite strategy and I haven't even tried it in GC2.

As for the effect, some of the minors are not concerned with IP and the majors will trade if they are in a bind. Influence is your last priority when you need stuff to fight a war that you are losing.

You trade IP and all other things in the trade/diplomacy window. Offer what you wish and select what you want in return they will accept or reject. Keep trying until they accept and click okay. The IP do not come from a specific planet but from their gross total. It might or might not effect their sphere depending on how close they are to your borders and how much you traded for.

ok but what about planet influence? in screens there are planet iinfluence points so if we speculate that i sell all IP why my planet has IP points too? if u sell all your influence to another race could u see all your planets defect to this race?
the situation is not totally clear for now, but i trust that stardock will have done a great job

That would actually make sense. Thus if you sell your complete pool, it's empty. And it slowly starts to fill up again each turn as your planets generate new influence points.

Selling you whole pool has a major impact on the UP ratio's though.

is this actually true? if you sell all your 'accumulated' points it does not affect your influence radius and starts to build again? And that the influence points are used in the UP and not your overal sphere of influence? Is anyone absolutely sure of this or could stardock confirm the algorythm used please.

Nope, I cannot confirm this as a fact. But since Peace Phoenix is a gammatester he might know how it works.
Only someone from Stardock could spoil the true beans though. So perhaps mr Frogboy himself could help us out here?

ESTABLISHED CAPS LOCK ISN'T REALLY A PROBLEM.FOR WHAT CONCERN THE LANGUAGE IT'S NOT MY FIRST LANGUAGE SO U COULD BE MORE KIND WRITING POST.
IF U IGNORE OR WHATEVER U DO READING MY POST IS YOUR PROBLEM AND FOR ME DOESN'T MATTER SO DON'T WRITE SIMILAR DUMBASS REPLY

The way Peace Phoenix describes it was the way it worked in GC1, and though I haven't looked at that specifically I can only assume it's the same case in GC2. IP equates to UP votes, nothing more.

I've got the same impression.

i'm a little confused about the system of IP. if i produce for example +1000 IP per turn at the 39th turn i will have 39000 IP and at the 100th i will have 100000 IP? in this way the system works?

Now I'm confused - is IP accumulated and spent every Dec at the UP, so that in the example above you will have 12,000 at the beginning of Dec and 0 after the meeting AND there is some off-screen "bank" where all of the IP's you have ever accumulated are totaled for Influence boundary determination purposes?

I thought/assumed that the Influence boundaries were based on the relative strength of the civilization's planets, attenuated by the distance from those planets and modified by other items such as super projects/wonders and Influence(r) Starbases. (And maybe physical presence of ships?)