This is similar to my thread on evidence posted a year ago. I've accumulated some observations about how these words are used and worked on how they should be used.
On skepticism, I noticed that when people refer to being skeptical what they typically mean is that they are biased against something. If someone says, "I'm skeptical of x", he really means that his general understanding of things pertaining to that specific matter or specific understanding of that matter is incompatible with the new proposition. Because everyone must assume some fundamental truths to begin thinking about anything more specific, you could claim to be skeptical in general more or less broadly within the realm of those assumptions depending on how extensive the assumptions are. But, when someone claims skepticism about x it is often a case of having a preference for a manifestly contradicting notion, which is really "bias".
On expertise, I noticed that this word is mostly used when talking about a topic about which the speaker is admittedly ignorant, referring to someone else. When the supposed expert is making the claim about himself he is marketing something. In doubt of the concept of "expertise", I tried to think of how to determine whether one is an expert. Suppose you an expert on everything. Does that mean you know 90% of everything? How would you know whether you know 90% of everything? It is impossible. To know whether you know 90% of everything you would need to know everything so that you know what 10% you are missing. Does it mean that you know more than someone else? The same problem applies to that. Do you put more effort into learning? That helps; yet, confidence does not equal knowledge. I can't see how the concept of expertise is practically anything but a rhetorical persuasion device.
A sample case to think about for skepticism is James Randi on homeopathy. He said that there is a lot of writing on how it works and little on whether it works. I don't know about that; I'll assume it is true. So, is he skeptical about whether homeopathy works? Based on that given reason he is. I have a different reason for being against it. The claim of homeopathy is that medicine samples with no active ingredient (only water) retain changes by the presence of the ingredient before dilution. On the face it that seems absurd to me because you could not guess what the effect of that altered state would be even assuming there are any. Based on that reason I'm not skeptical; I'm biased.
On skepticism, it seems either one is agnostic on the subject, so being unsure they become skeptical; or that with new streams of information or evidence, they begin to distrust the current or previous percieved view of things. Someone can say that they are skeptical about certain things, but really they are witholding a hard opinion; or that they do not accept the mainstream view of said subject based on their own research and evidence they have come across. I feel like a bias in a way would be a given, that they are bias against the accepted view. "I'm skeptical about widgets," well either the person does not know anything about widgets, and is forfeiting an opinion about widgets, or they've read about widgets and concluded that they do not like them. I can also see a bit of both coming into play, one may be told about widgets, but they want to know for themselves about widgets, and what they find counters what they were always told. With the bias it can be a "tipping point" from one degree to the other on accepting something cautiously, or turning away from it.
On expertise I suppose your idea of this contrasts with that of a specialist, but when I think of expertise I generally think of someone is is an expert in said field, that they studied it or work in that field, etc. Though, with experts, you can come across bias or contrasting views. Someone can say they are an expert in economics, but may be a Keynesian; or someone can say they specialize in economics and be a Keynesian. The latter seems more acceptable, there's less debate on what they know. A Keynesian or Austrian saying "I specialize in economics," well that's there field and I accept they may know a lot about economics, but to say "I'm an expert in economics" does seem rather pompous, because with that level of confidence they may conclude their bias is final. By the mere use of the language it perpetrates a sense of arrogance. When someone says they specialize it only concludes it's their area of study, they would know more than the layman, and expert concludes they know everything, and are without fault.
I think skepticism is an ultimately stupid positon, and only works with the context and limits of things. I think could be illustrated by the more Austrian / "German Subjectivist" conflict of the more concrete notion of will (assert truth) vs the more mainstream fuzzy concept of abstract skepticism (find truth)
"As in a kaleidoscope, the constellation of forces operating in the system as a whole is ever changing." - Ludwig Lachmann
"When A Man Dies A World Goes Out of Existence" - GLS Shackle
I think skepticism is an ultimately stupid positon...
I'm skeptical of that.
And you are skeptical of skepticism.
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It's easy to refute an argument if you first misrepresent it. William Keizer
I'm not skeptical at all, I'm stating it doesn't make sense as the ultimate foundation of anything. You can doubt away to the point of irrelvancy in conversation and grammatical cuteness as much as you'd like.
Implying the line between "I'm skeptical of that" to that of "I don't believe that's the case"? In a way, they are both the same, but I suppose being skeptical implies witholding knowing.