Not all recipes call for the same substitution for the same ingredient. And not everyone has the same philosophy about how to substitute.
For instance, eggs. There are several different uses for them in recipes; binding, leavening, moisture, protein content, etc. There are several different substitutions and most do some of those things better than others. Picking a good egg substitute, or choosing to simply leave the eggs out, requires knowledge and experience, or at least a flow chart.
There's enough of an art to it that I'd rather see how others solved the problem than consult a browser plugin that seems geared more to sell me stuff than to help me solve problems.