Pillars happen when a large piece of the original candle stands up by itself. (Standing pieces created by wax flow are mountains, not pillars.)
This shape signals that this work will bring public or community attention to the results or process of the spell.
A single pillar indicates leadership or someone be considered responsible for something.
Two indicates partnership, either romantic or business.
What To Do:
This sign almost always means publicity or at least a large amount of gossip. If you do not want those things, consider doing some 'shut up' work.