Welcome to the forum, Quantum.
I understand, first of all, very well what Darwin meant by natural selection. The problem is that it doesn't do what he and the rest of Darwinists want it to do. It does not add to the possible varieties of a population, it subtracts from them.
It is selection which involves the death or non-reproductivity of a percentage of the original population. This eliminates a certain amount of potential for variation from the population's gene pool every time it happens. The remnant population begins to climb something called a 'fitness peak', which means it becomes more and more 'fit' for one particular environment -- at the expense of being unable to vary enough to cope with any other environment. This is how we get our endangered species.
Natural selection exists, but it is not a boon for evolutionists. Check a course or text in population genetics.
Along those lines, it is important to understand that although mutations can produce new alleles, sexual reproduction will most likely eliminate them from the population, whether or not they are beneficial. Sexual reproduction does that. The only way you can get a new allele to be present in a population is to have a small, isolated population. Then you will get some kind of recessive gene expression which marks that population as different from a parent population. But this never, but never, means a new form or function -- it simply means a variation on what was already there.
The idea of the article leading this thread is entirely story-telling with no basis in data at all. It is, as is almost all evolutionary articles, grand at imagination and story-telling and abysmally short on facts, data, or anything at all to do with real science.
edit: by the way, sickle cell is NOT a good mutation. It is a deadly mutation which happens to have a beneficial side effect as long as it is not homozygotic.
And no one is arguing against viruses managing to mutate. But please note they are still viruses and still identifiable as to type of virus. No one is arguing variation.