user4192: From cardano.org:

Saturation Parameter (K)
Saturation is a term used to indicate that a particular stake pool has more stake delegated to it than is ideal for the network, while k is the targeted number of desired pools. Once a pool reaches the point of saturation, it will offer diminishing rewards. The saturation mechanism was designed to prevent centralization by encouraging delegators to delegate to different stake pools, and to incentivize operators to set up alternative pools so that they can continue earning maximum rewards. Saturation, therefore, exists to preserve the interests of both ada holders delegating their stake and stake pool operators, and to prevent any single pool from becoming too large.

But, if a stake pool operator starts a second stake pool on the same server as soon as a stake pool gets saturated, how does that help decentralization? It's still the same guy and the same server. What am I missing here?

user2042: The saturation parameter (k) should be considered alongside the pledge influence parameter (a0).
The purpose of a0 is to incentivize pool operators to delegate a larger pledge to their own pool by providing greater rewards to pools with a higher pledge. The idea being that this will encourage operators to concentrate their available Ada into a smaller number of pools, rather than creating lots of pools with a lower pledge.
This is the theory, and I believe it is still a work in progress in terms of tweaking those mechanics as it would seem that this may not be providing a sufficient incentive for pool operators to behave in this way.

user2901: As the article says, pool saturation helps to "divide" delegated ADA into different pools, this mean that not only big pools can be chosen from the algorithm to verify a block but also the smaller one. In this way the job is split and the decentralization is higher.
If a SPO decide to create a second pool, the level of decentralization is lower. True decentralization is reached only if every operator manage one and only one pool.
You can read more here

4192: <p>From <a href="https://cardano.org/stake-pool-operation/" rel="nofollow noreferrer">cardano.org</a>:</p>
<blockquote>
<h2>Saturation Parameter (K)</h2>
<p>Saturation is a term used to indicate that a particular stake pool has more stake delegated to it than is ideal for the network, while k is the targeted number of desired pools. Once a pool reaches the point of saturation, it will offer diminishing rewards. The saturation mechanism was designed to prevent centralization by encouraging delegators to delegate to different stake pools, and to incentivize operators to set up alternative pools so that they can continue earning maximum rewards. Saturation, therefore, exists to preserve the interests of both ada holders delegating their stake and stake pool operators, and to prevent any single pool from becoming too large.</p>
</blockquote>
<p>But, if a stake pool operator starts a second stake pool on the same server as soon as a stake pool gets saturated, how does that help decentralization? It's still the same guy and the same server. What am I missing here?</p>
 2042: <p>The saturation parameter (k) should be considered alongside the pledge influence parameter (a0).</p>
<p>The purpose of a0 is to incentivize pool operators to delegate a larger pledge to their own pool by providing greater rewards to pools with a higher pledge. The idea being that this will encourage operators to concentrate their available Ada into a smaller number of pools, rather than creating lots of pools with a lower pledge.</p>
<p>This is the theory, and I believe it is still a work in progress in terms of tweaking those mechanics as it would seem that this may not be providing a sufficient incentive for pool operators to behave in this way.</p>
 2901: <p>As the article says, pool saturation helps to &quot;divide&quot; delegated ADA into different pools, this mean that not only big pools can be chosen from the algorithm to verify a block but also the smaller one. In this way the job is split and the decentralization is higher.</p>
<p>If a SPO decide to create a second pool, the level of decentralization is lower. True decentralization is reached only if every operator manage one and only one pool.</p>
<p>You can read more <a href="https://singlepoolalliance.net/about-us.html" rel="noreferrer">here</a></p>
